* Pdb lock issue

* Added comments

* Todo changes for coverlet inproc datacollector

* Fixing UT

* Fixing the encoding and adding the BuildFromSource condition.

…sions (#2041)

* Adding PEReader to extensions

* Registrar Null Fixed

* Adding RunSpecific UTs

Reduced the version of System.Runtime.InteropServices.RuntimeInformation to 4.0.0

* Fixed incorrect timeout message when test host crashes/exits

* Added tests

* Update ProxyExecutionManagerTests.cs

* Update ProxyOperationManager.cs

* Update ProxyExecutionManagerTests.cs

* Fix the error reported for incompatible framework to give complete framework name.
* Fixing the unit tests
* Fixed acceptance test

* Cleaning the remaining set of dependencies for source build.
a. Microsoft.Build.Framework and Microsoft.Build.Utilities.Core to source built version: 16.0.461
b. Microsoft.Extensions.DependencyModel to source built version: 3.0.0-preview4-27615-11
c. Removed the redundant reference to Microsoft.Internal.Dia.Interop
d. Adding check for source build for StyleCop.Analyzers

* Fixing the failures
* Adding System.Memory and System.Runtime.CompilerServices.Unsafe to portable package
* Correcting the number of files.
* Made the packages configurable via the props file.
* Fixing versions in the unit test project as well.
* Removing redundant dependency in the testhost nuspec