Post 3.0 merge fixup

This cleans up all of the PROTOTYPE comments around using the 3.0 SDK
inside the DIM branch.

docs/contributing/Building, Debugging, and Testing on Windows.md

@@ -19,7 +19,7 @@ The minimal required version of .NET Framework is 4.7.2.
     - Ensure C#, VB, MSBuild, .NET Core and Visual Studio Extensibility are included in the selected work loads
     - Ensure Visual Studio is on Version "RC1" or greater
     - Ensure "Use Previews" is checked in Tools -> Options -> Projects and Solutions -> .NET Core
-1. [.NET Core SDK 3.0 Preview 3](https://dotnet.microsoft.com/download/dotnet-core/3.0) [Windows x64 installer](https://dotnet.microsoft.com/download/thank-you/dotnet-sdk-3.0.100-preview3-windows-x64-installer)
+1. [.NET Core SDK 3.0 Preview 4](https://dotnet.microsoft.com/download/dotnet-core/3.0) [Windows x64 installer](https://dotnetcli.azureedge.net/dotnet/Sdk/3.0.100-preview4-010391/dotnet-sdk-3.0.100-preview4-010391-win-x64.exe )
 1. [PowerShell 5.0 or newer](https://docs.microsoft.com/en-us/powershell/scripting/setup/installing-windows-powershell). If you are on Windows 10, you are fine; you'll only need to upgrade if you're on Windows 7. The download link is under the "upgrading existing Windows PowerShell" heading.
 1. Run Restore.cmd
 1. Open Roslyn.sln

eng/Versions.props

@@ -72,8 +72,6 @@
     <!-- PROTOTYPE(DefaultInterfaceImplementation): The MicrosoftNetCoreILAsmVersion was 2.0.0 -->
     <MicrosoftNetCoreILAsmVersion>3.0.0-preview4-27420-71</MicrosoftNetCoreILAsmVersion>
     <MicrosoftNETCorePlatformsVersion>2.1.2</MicrosoftNETCorePlatformsVersion>
-    <!-- PROTOTYPE(DefaultInterfaceImplementation): The MicrosoftNETCoreRuntimeCoreCLRVersion was 2.0.0 -->
-    <MicrosoftNETCoreRuntimeCoreCLRVersion>3.0.0-preview4-27420-5</MicrosoftNETCoreRuntimeCoreCLRVersion>
     <!-- Using a private build of Microsoft.Net.Test.SDK to work around issue https://github.com/Microsoft/vstest/issues/1764 -->
     <MicrosoftNETTestSdkVersion>15.9.0-dev2</MicrosoftNETTestSdkVersion>
     <MicrosoftNETCoreTestHostVersion>1.1.0</MicrosoftNETCoreTestHostVersion>
@@ -319,12 +317,6 @@
       https://vside.myget.org/F/vs-impl/api/v3/index.json;
       https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json;
       https://dotnet.myget.org/F/system-commandline/api/v3/index.json;
-      
-      <!--
-      PROTOTYPE(DefaultInterfaceImplementation): added the https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json (Microsoft.NETCore.App) and 
-                                                 https://dotnetfeed.blob.core.windows.net/dotnet-coreclr/index.json (Microsoft.NETCore.ILAsm) sources below
-      -->
-      https://dotnetfeed.blob.core.windows.net/dotnet-core/index.json;
       https://dotnetfeed.blob.core.windows.net/dotnet-coreclr/index.json;
     </RestoreSources>
   </PropertyGroup>

eng/build.ps1

@@ -223,8 +223,6 @@ function BuildSolution() {
     # an arcade bug
     # https://github.com/dotnet/arcade/issues/2220
     $quietRestore = !($ci -or ($bootstrapDir -ne ""))
-
-    # PROTOTYPE(DefaultInterfaceImplementation): Added "netcoreapp3.0%3B", original value was "netcoreapp2.1"
     $testTargetFrameworks = if ($testCoreClr) { "netcoreapp3.0%3Bnetcoreapp2.1" } else { "" }
     
     $ibcSourceBranchName = GetIbcSourceBranchName

eng/build.sh

@@ -249,7 +249,6 @@ function BuildSolution {
     mono_tool="/p:MonoTool=\"$mono_path\""
   elif [[ "$test_core_clr" == true ]]; then
     test=true
-    # PROTOTYPE(DefaultInterfaceImplementation): Added /p:TestTargetFrameworks=netcoreapp3.0%3Bnetcoreapp2.1
     test_runtime="/p:TestRuntime=Core /p:TestTargetFrameworks=netcoreapp3.0%3Bnetcoreapp2.1"
     mono_tool=""
   fi

eng/common/tools.ps1

@@ -94,9 +94,6 @@ function InitializeDotNetCli([bool]$install) {
   # Don't resolve runtime, shared framework, or SDK from other locations to ensure build determinism
   $env:DOTNET_MULTILEVEL_LOOKUP=0
 
-  # PROTOTYPE(DefaultInterfaceImplementation): Set this to be able to run apps targeting netcoreapp2.1 against netcoreapp3.0
-  $env:DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX=2
-
   # Disable first run since we do not need all ASP.NET packages restored.
   $env:DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
 

eng/common/tools.sh

@@ -83,9 +83,6 @@ function InitializeDotNetCli {
   # Don't resolve runtime, shared framework, or SDK from other locations to ensure build determinism
   export DOTNET_MULTILEVEL_LOOKUP=0
 
-  # PROTOTYPE(DefaultInterfaceImplementation): Set this to be able to run apps targeting netcoreapp2.1 against netcoreapp3.0
-  export DOTNET_ROLL_FORWARD_ON_NO_CANDIDATE_FX=2
-
   # Disable first run since we want to control all package sources
   export DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1