To have a good integration with xunit we need give the control of entry point to it.

This PR #3494 will change the static extension generation emitting a custom static method that will be used by the xunit entry point codegen to remove the friction between v3 codege entry point and our own.
xUnit will set GenerateTestingPlatformEntryPoint=false and will insert our codegen static registration method in it's codegen.

<TestingPlatformBuilderHook Include="98058041-B5B6-4A75-9834-58E6DF796A22" Condition=" '$(GenerateTestingPlatformEntryPoint)' == 'True' " >

AB#2200938