Annotate RAR SearchPaths added because they're "next to a reference"

[surayya-MS]

Fixes #9408

Context

When building this project from a Developer Command Prompt:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <TargetFramework>net472</TargetFramework>
  </PropertyGroup>

  <ItemGroup>
    <Reference Include="$(DevEnvDir)\..\..\MSBuild\Current\Bin\Microsoft.Build.dll" />
    <Reference Include="Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" />
  </ItemGroup>

</Project>

That produces this RAR snippet for Framework:

Primary reference "Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a". (TaskId:59)
    Resolved file path is "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin\Microsoft.Build.Framework.dll". (TaskId:59)
    Reference found at search path location "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin". (TaskId:59)
        For SearchPath "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin". (TaskId:59)
        Considered "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin\Microsoft.Build.Framework.winmd", but it didn't exist. (TaskId:59)

Changes Made

When calculating resolvers to resolve a reference we currently adding DirectoryResolvers for each directories of the reference's dependees:

msbuild/src/Tasks/AssemblyDependency/ReferenceTable.cs

Lines 1282 to 1286 in 07fd5d5

	var parentReferenceFolders = new List<string>();
	foreach (Reference parentReference in reference.GetDependees())
	{
	CalculateParentAssemblyDirectories(parentReferenceFolders, parentReference);
	}

Added ParentAssembly property to the Resolver to save that info to log it later for searchpath.
Added new type of log message for this specific case:

For SearchPath {searchPath}" (added by referencing assembly {parentAssemly}).

Now same example produces:

Primary reference "Microsoft.Build.Framework, Version=15.1.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a". (TaskId:21)
      Resolved file path is "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin\Microsoft.Build.Framework.dll". (TaskId:21)
      Reference found at search path location "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin". (TaskId:21)
          For SearchPath "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin" (added by referencing assembly "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin\Microsoft.Build.dll"). (TaskId:21)
          Considered "C:\Program Files\Microsoft Visual Studio\2022\Preview\MSBuild\Current\Bin\Microsoft.Build.Framework.winmd", but it didn't exist. (TaskId:21)

Testing

Unit test for new log message and manual test

Notes

[rokonec]

Please consider changing value tuple (string, string) to readonly record struct for maintanability purposes