Switch to a 2.0 version of our stage 1 bootstrap compiler (#14908)

build/Targets/Settings.props

@@ -11,7 +11,7 @@
     <NuGetPackageRoot Condition="'$(NuGetPackageRoot)' == '' and '$(OS)' == 'Windows_NT'">$(UserProfile)\.nuget\packages</NuGetPackageRoot>
     <NuGetPackageRoot Condition="'$(NuGetPackageRoot)' == '' and '$(OS)' != 'Windows_NT'">$(HOME)\.nuget\packages</NuGetPackageRoot>
     <ToolsetCompilerPackageName>Microsoft.Net.Compilers</ToolsetCompilerPackageName>
-    <ToolsetCompilerPackageVersion>1.3.2</ToolsetCompilerPackageVersion>
+    <ToolsetCompilerPackageVersion>2.0.0-rc2-61102-09</ToolsetCompilerPackageVersion>
     <RoslynDiagnosticsNugetPackageVersion>1.2.0-beta2</RoslynDiagnosticsNugetPackageVersion>
     <RoslynDiagnosticsPropsFilePath>$(NuGetPackageRoot)\Microsoft.Net.RoslynDiagnostics\$(RoslynDiagnosticsNugetPackageVersion)\build\Microsoft.Net.RoslynDiagnostics.props</RoslynDiagnosticsPropsFilePath>
     <RoslynBuildUtilFilePath>$(NuGetPackageRoot)\Roslyn.Build.Util\0.9.4-portable\lib\dotnet\Roslyn.MSBuild.Util.dll</RoslynBuildUtilFilePath>

build/ToolsetPackages/project.json

@@ -5,7 +5,7 @@
     "MicroBuild.Plugins.SwixBuild": "1.0.71",
     "Microsoft.NETCore.Platforms": "1.0.1",
     "Microsoft.DiaSymReader.Native": "1.5.0-beta1",
-    "Microsoft.Net.Compilers": "1.3.2",
+    "Microsoft.Net.Compilers": "2.0.0-rc2-61102-09",
     "Microsoft.Net.RoslynDiagnostics": "1.2.0-beta2",
     "FakeSign": "0.9.2",
     "xunit.assert": "2.1.0",