Only extract mlaunch once per build (#879)

Author: premun

src/Microsoft.DotNet.XHarness.CLI/Microsoft.DotNet.XHarness.CLI.csproj

@@ -11,7 +11,7 @@
     <!-- Mono.Options is apparently not strong-name signed -->
     <NoWarn>CS8002;</NoWarn>
 
-    <MlaunchDestinationDir>$(BaseIntermediateOutputPath)/mlaunch</MlaunchDestinationDir>
+    <MlaunchDestinationDir Condition="'$(TargetFrameworks)' == '' OR $(TargetFrameworks.EndsWith($(TargetFramework)))">$(BaseIntermediateOutputPath)/mlaunch</MlaunchDestinationDir>
 
     <!-- When updating these URLs, avoid using 'latest' url as these are redirects and can make the same commit build differently on different days -->
     <WindowsAndroidSdkUrl>https://dl.google.com/android/repository/platform-tools_r29.0.6-windows.zip</WindowsAndroidSdkUrl>