Work around uninstall issue with our VSIX

There is an issue uninstalling our VSIX via the standard tooling at the
moment. Using the wildfire approach for now to unblock PRs

build/scripts/build.ps1

@@ -262,8 +262,9 @@ function Deploy-VsixViaTool() {
     $both = Get-VisualStudioDirAndId
     $vsDir = $both[0].Trim("\")
     $vsId = $both[1]
+    $hive = "RoslynDev"
     Write-Host "Using VS Instance $vsId at `"$vsDir`""
-    $baseArgs = "/rootSuffix:RoslynDev /vsInstallDir:`"$vsDir`""
+    $baseArgs = "/rootSuffix:$hive /vsInstallDir:`"$vsDir`""
     $all = @(
         "Vsix\CompilerExtension\Roslyn.Compilers.Extension.vsix",
         "Vsix\VisualStudioSetup\Roslyn.VisualStudio.Setup.vsix",
@@ -275,24 +276,18 @@ function Deploy-VsixViaTool() {
 
     Write-Host "Uninstalling old Roslyn VSIX"
 
-    # Reverse the extension list so we uninstall in the proper order so that dependencies line up
-    [array]::Reverse($all)
-
-    foreach ($e in $all)
-    {
-        $name = Split-Path -leaf $e
-        $filePath = Join-Path $configDir $e
-        $fullArg = "-u $baseArgs $filePath"
-        Write-Host "`tUninstalling $name"
-        Exec-Command $vsixExe $fullArg | Out-Host
+    # Actual uninstall is failing at the moment using the uninstall options. Temporarily using 
+    # wildfire to uninstall our VSIX extensions
+    $extDir = Join-Path ${env:USERPROFILE} "AppData\Local\Microsoft\VisualStudio\15.0_$($vsid)$($hive)"
+    if (Test-Path $extDir) {
+        foreach ($dir in Get-ChildItem -Directory $extDir) {
+            $name = Split-Path -leaf $dir
+            Write-Host "`tUninstalling $name"
+        }
+        Remove-Item -re -fo $extDir
     }
 
     Write-Host "Installing all Roslyn VSIX"
-
-    # Reverse the extension list so we install in the proper order so that dependencies line up
-    # Note: Only required as long as we reverse the list for uninstall above
-    [array]::Reverse($all)
-
     foreach ($e in $all) {
         $name = Split-Path -leaf $e
         $filePath = Join-Path $configDir $e