* [wasm] Add support for per-project customization of helix work items

Currently, for sending tests to helix:
1. the project binaries are zipped, as part of the project build
2. then separate helix targets files build that adds helix items for
   those zip files.
    - for wasm, we test with multiple 'scenarios' - like v8, browser, and
    nodejs.
    - so, 3 helix work items are submitted per zip file

- If a test project needs to have any customizations, for example, for
  testing crypto with a managed implementation, and subtlecrypto, which
  would require:
  - passing different arguments to xharness, in case of managed, and
    subtlecrypto
  - and this should be done only for the browser case
  - Currently, this would need this would need to be done in
  `sendtohelix-wasm.targets` special casing for the test project, and
  scenario.

- We add support for importing `$(ProjectName).helix.targets`, and
  calling a special target in that to add helix items, as needed.

- This targets file can be set in the test project like:
```xml
<HelixTargetsFile Condition="'$(TargetOS)' == 'Browser'">wasm.helix.targets</HelixTargetsFile>
```
  - it will get deployed next to the zip file, and picked up automatically

```xml
<Project>
  <PropertyGroup>
    <_CryptoProjectName>System.Security.Cryptography.Tests</_CryptoProjectName>
    <System_Security_Cryptography_Tests_TargetName Condition="'$(Scenario))' == 'WasmTestOnBrowser'">System_Security_Cryptography_Tests_Targ
et</System_Security_Cryptography_Tests_TargetName>
  </PropertyGroup>

  <Target Name="System_Security_Cryptography_Tests_Target">
    <ItemGroup>
      <HelixWorkItem Include="$(Scenario)-managed-$(_CryptoProjectName)">
        <PayloadArchive>$(TestArchiveTestsDir)$(_CryptoProjectName).zip</PayloadArchive>
        <Command>$(HelixCommand)</Command>
        <Timeout>$(_workItemTimeout)</Timeout>
      </HelixWorkItem>

      <HelixWorkItem Include="$(Scenario)-subtlecrypto-System.Security.Cryptography.Tests">
        <PayloadArchive>$(TestArchiveTestsDir)$(_CryptoProjectName).zip</PayloadArchive>
        <Command>$(HelixCommand)</Command>
        <Timeout>$(_workItemTimeout)</Timeout>

        <PreCommands Condition="'$(OS)' == 'Windows_NT'">set &quot;WasmXHarnessArgs=--web-server-use-cors&quot;</PreCommands>
        <PreCommands Condition="'$(OS)' != 'Windows_NT'">export &quot;WasmXHarnessArgs=--web-server-use-cors&quot;</PreCommands>
      </HelixWorkItem>
    </ItemGroup>
  </Target>
```

- The targets file *must* have these:
    - a property named like `System_Security_Cryptography_Tests_TargetName`, for a
      test project named `System.Security.Cryptography.Tests`
    - if this property is not set, then the default behavior of adding
      work items will run
    - The target should add any items it needs to to `@(HelixWorkItem)`.
      - Examples of adding these can be seen in `sendtohelix*` project files

- Remember that all these properties, and targets get imported into the
  msbuild *global* namespace, so make sure to use unique names to avoid
  conflicts with other test projects.

Future work: this commit only enables it for wasm/library tests, but it should
be easy to extract it out, but needs some testing.

* [wasm] Helix: test with, and without subtle crypto

* disable non-wasm builds

* address review feedback

* Address review feedback

* Fix typo

* Revert "disable non-wasm builds"

This reverts commit 7ef99e81f82200189dd3f61eeaf00d6ca4ced6d4.

* Update src/libraries/System.Security.Cryptography/tests/wasm.helix.targets
Co-authored-by: NEric Erhardt <eric.erhardt@microsoft.com>

* Address review feedback

* remove debug spew

* Change the way helix extension targets are discovered.

The new approach:

To run a custom project specific target for adding/editing @(HelixWorkItem):

- In the project add:
    `<HelixTargetsFile Condition="'$(TargetOS)' == 'Browser'">wasm.helix.targets</HelixTargetsFile>`

    - This file gets copied next to the test archive as $(MSBuildProjectName).helix.targets

- In this `wasm.helix.targets` file, add to $(HelixExtensionTargets) to run your custom target

```xml
  <PropertyGroup Condition="'$(IsRunningLibraryTests)' == 'true' and '$(Scenario)' == 'WasmTestOnBrowser'">
    <HelixExtensionTargets>$(HelixExtensionTargets);_AddHelixCrypoItems</HelixExtensionTargets>
```

- The extension target will be called after the default items are added
  to `@(HelixWorkItem)`.
- Useful properties to condition on: $(Scenario), $(IsRunningLibraryTests)
- And add to, change, or remove from @(HelixWorkItem)

Example:
```xml
  <Target Name="_AddHelixCrypoItems">
    <ItemGroup>
      <!-- remove the existing item -->
      <HelixWorkItem Remove="@(HelixWorkItem)" Condition="'%(OriginalFileName)' == '$(_CryptoProjectName)'" />

        <!-- add two new ones - managed, and subtylecrypto -->
      <HelixWorkItem Include="$(WorkItemPrefix)managed-$(_CryptoProjectName)">
        <PayloadArchive>$(TestArchiveTestsDir)$(_CryptoProjectName).zip</PayloadArchive>
        <Command>$(HelixCommand)</Command>
        <Timeout>$(_workItemTimeout)</Timeout>
        <OriginalFileName>$(_CryptoProjectName)</OriginalFileName>
      </HelixWorkItem>

      <HelixWorkItem Include="$(WorkItemPrefix)subtlecrypto-$(_CryptoProjectName)">
        <PayloadArchive>$(TestArchiveTestsDir)$(_CryptoProjectName).zip</PayloadArchive>
        <Command>$(HelixCommand)</Command>
        <Timeout>$(_workItemTimeout)</Timeout>
        <OriginalFileName>$(_CryptoProjectName)</OriginalFileName>

        <PreCommands Condition="'$(OS)' == 'Windows_NT'">set &quot;WasmXHarnessArgs=%WasmXHarnessArgs% --web-server-use-cop&quot;</PreCommands>
        <PreCommands Condition="'$(OS)' != 'Windows_NT'">export &quot;WasmXHarnessArgs=$WasmXHarnessArgs --web-server-use-cop&quot;</PreCommands>
      </HelixWorkItem>

      <_CryptoHelixItem Include="@(HelixWorkItem)"
                        Condition="$([System.String]::new('%(HelixWorkItem.Identity)').EndsWith('-$(_CryptoProjectName)'))" />
    </ItemGroup>

    <Error Text="Something went wrong. Expected to have only two work items for $(_CryptoProjectName). But got @(_CryptoHelixItem)"
           Condition="@(_CryptoHelixItem->Count()) != 2" />
  </Target>
```

* cleanup

* Move WBT specific stuff into the target too. This will make it simpler to move it off into a targets file later

* fix build

* fix libtests

* fix wbt

* [wasm] Bump helix timeout to 90mins for debugger tests on windows
Co-authored-by: NEric Erhardt <eric.erhardt@microsoft.com>