Infrastructure updates: CLI:master -> release/2.1.3xx (#8541)

* Repairing the first pass call to 'dotnet msbuild'; CLI:master (#8488)

* '$ExtraParametersNoTargets', which is used on the first pass call to 'dotnet msbuild', currently is of type 'string' not 'List'1' as is '$ExtraParameters'. This results in the non-honoring of any parameter other than parameter one. Solution: Make a copy of '$ExtraParameters' to '$ExtraParametersNoTargets' of type 'List'1' and remove the targets from the list.

* Swallow the boolean output from '$ExtraParametersNoTargets.Remove'

* Specifically capture "/t:" or "/target:" only.

* The "${arg,,}" syntax works well on dev and Jenkins OSX machines but does not work correctly on VSO build machines [likely a lower version of bash on VSO machines]. Therefore, using 'awk' to transforming to lower case. (#8497)

* Orchestrated final publish; CLI:master (#8504)

* Orchestrated final publish: https://github.com/dotnet/core-eng/issues/2407

* Changes per code review...

* The orchestrated "PackageVersion" type variables should not be used in any of the 'proj' files of the built build tools under: "build_projects"

build_projects/dotnet-cli-build/dotnet-cli-build.csproj

@@ -14,7 +14,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NETCore.App" Version="$(MicrosoftNETCoreAppPackageVersion)" />
+    <PackageReference Include="Microsoft.NETCore.App" Version="2.1.0-preview1-26116-04" />
     <PackageReference Include="Microsoft.Build" Version="15.4.8" />
     <PackageReference Include="Microsoft.Build.Utilities.Core" Version="15.4.8" />
     <PackageReference Include="Microsoft.CSharp" Version="4.0.1" />