Fixing aspnet/JitBench#80 (#15764)

- Issue was fixed with this: aspnet/JitBench#82
- Set the UseSharedCompilation=false to avoid that the `VBCSCompiler.exe` stays running.

Author: José Rivero

tests/scripts/run-xunit-perf.cmd

@@ -7,6 +7,8 @@
 setlocal ENABLEDELAYEDEXPANSION
   set ERRORLEVEL=
   set DOTNET_MULTILEVEL_LOOKUP=0
+  set UseSharedCompilation=false
+
   set BENCHVIEW_RUN_TYPE=local
   set CORECLR_REPO=%CD%
   set LV_SANDBOX_DIR=%CORECLR_REPO%\bin\sandbox

tests/src/performance/Scenario/JitBench/JitBenchHarness.cs

@@ -20,6 +20,10 @@ class JitBenchHarness
     {
         static void Main(string[] args)
         {
+            // The flag below is set to false to prevent the VBCSCompiler.exe hanging around
+            // after the performance execution finished and preventing the deletion of the folder.
+            Environment.SetEnvironmentVariable("UseSharedCompilation", "false");
+
             var options = JitBenchHarnessOptions.Parse(args);
 
             SetupStatics(options);
@@ -395,7 +399,7 @@ private static void ValidateEnvironment(IDictionary<string, string> environment)
         }
 
         private const string JitBenchRepoUrl = "https://github.com/aspnet/JitBench";
-        private const string JitBenchCommitSha1Id = "36db11e7ab15e96af10d995a048a1476b4e73d43";
+        private const string JitBenchCommitSha1Id = "1235b8ed0e867dae0be50ba9467f5028c813c4fd";
         private const string JitBenchTargetFramework = "netcoreapp2.1";
         private const string EnvironmentFileName = "JitBenchEnvironment.txt";