* Compare lines instead of using AssertXml when validating PDBs.

AssertXml doesn't validate ordering.

* Reorder expected PDB XML nodes to match actual order

* Update to the latest Microsoft.DiaSymReader.* packages.

* Enable embedding sources to Windows PDBs

Enable few more rules and fix issues identified these rules.

Also added issue IDs for the disabled rules due to lack of a fixer/fix all experience.

The PDB path which is written into the PE file should respect the
`/pathmap` option passed to the compiler.  This is necessary to ensure
that PEs can be deterministic when built from different source paths.

The feature flag `pdb-path-determinism` is being kept for the time
being.  Even though it's a feature flag it still seems inappropriate to
break customers in a point release.  Deferring the removal until the
next major release to give customers time to react.  This issue tracks
removing the flag:

https://github.com/dotnet/roslyn/issues/19592

closes #9813

* Ref assemblies make a best effort to emit with determinism
* Fixing CopyRefAssembly message output
* CopyRefAssembly logs when input isn't ref assembly
* CopyRefAssembly does assembly redirect.
* Compact error codes for C# 7.1

* Make sure errors are consistent when providing null vs empty key files during signing

* Addressed PR Comments

* Treat empty CryptoKeyFile as null

* More PR Comments

this doesn't replace or change anything yet, just bunch of Operation types for next step.

next step is creating CSharp/VBFactory which return these Operation type and replace callsite that return bound node with this.

after that, I will create xml/generator from Operation.xml.Generated.cs which can produce Operation.xml.Generated.cs

this is easy step. just spliting all IOperations as its own files and put them in its own folder

* refonly and refout on command-line and msbuild
* corresponding change to Emit API
* Metadata-only assembly use `throw null` bodies
* Can no longer produce netmodule with metadata only

Fixes #17802

* remove no-arg-constructors for ArgumentException from compiler

* fix all `new ArgumentException(nameof(paramname))` instances.

* update error

Fixes #10023.

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems?id=233669.

Fixes #14365.

Fixes https://devdiv.visualstudio.com/DevDiv/_workitems?id=217718.

Provide an API to get unreferenced assembly identities obects from the diagnostics reported about them.

Use tuple syntax in the compiler