Fix variables in restore-toolset.sh/.ps1

The productBuild variable got renamed in #49080 which caused errors.

Author: akoeplinger

eng/restore-toolset.ps1

@@ -9,8 +9,8 @@ function InitializeCustomSDKToolset {
   }
 
   # The following frameworks and tools are used only for testing.
-  # Do not attempt to install them in product build.
-  if ($productBuild) {
+  # Do not attempt to install them when building in the VMR.
+  if ($fromVmr) {
     return
   }
 

eng/restore-toolset.sh

@@ -6,8 +6,8 @@ function InitializeCustomSDKToolset {
   fi
 
   # The following frameworks and tools are used only for testing.
-  # Do not attempt to install them in product build.
-  if [[ $product_build == true ]]; then
+  # Do not attempt to install them when building in the VMR.
+  if [[ $from_vmr == true ]]; then
     return
   fi