Fix a variable re-definition that resulted in two git invocations per project build

Author: swgillespie

tests/dir.props

@@ -103,10 +103,6 @@
     <RestorePackages>false</RestorePackages>
   </PropertyGroup>
 
-  <PropertyGroup>
-    <BuildVersionFile>$(BaseIntermediateOutputPath)BuildVersion-$(OfficialBuildId).props</BuildVersionFile>
-  </PropertyGroup>
-
   <!-- If we want to overwrite the desired CoreCLR package version, we need to get the new version from the generated props file in bin/obj -->
   <Import Condition="'$(OverwriteCoreClrPackageVersion)' == 'true'" Project="$(BuildVersionFile)" />