find_vstool now verifies that the tool can be executed

This improvement is meant to discard tool binaries that cannot be run. This is useful when you have an old install of VS that is broken for whatever reason. Now, we will ensure the tool has a valid exit code

Tools/find_vstool.ps1

@@ -27,6 +27,16 @@ function EditBinCertificateIsValid() {
     }
 }
 
+
+function ToolCanBeExecuted {
+    param (
+        [string]
+        $Path
+    )
+    $null = & $Path
+    Write-Output ($LASTEXITCODE -gt 0)
+}
+
 $rootSearchPaths = @(
     [System.IO.Directory]::EnumerateFileSystemEntries("C:\Program Files", "*Visual Studio*", [System.IO.SearchOption]::TopDirectoryOnly),
     [System.IO.Directory]::EnumerateFileSystemEntries("C:\Program Files (x86)", "*Visual Studio*", [System.IO.SearchOption]::TopDirectoryOnly)
@@ -37,7 +47,7 @@ foreach ($searchPath in $rootSearchPaths) {
     foreach ($visualStudioFolder in $searchPath) {
         $matchingExes = [System.IO.Directory]::EnumerateFileSystemEntries($visualStudioFolder, $FileName, [System.IO.SearchOption]::AllDirectories)
         foreach ($matchingExe in $matchingExes) {
-            if (EditBinCertificateIsValid -Path $matchingExe) {
+            if ((EditBinCertificateIsValid -Path $matchingExe) -and (ToolCanBeExecuted -Path $matchingExe)) {
                 return $matchingExe
             }
         }