make-wrapper: fixup #14753 changes to make tests work

The tests need to expand passed variable and very carefully.
I could see no other easy way than to change single-quoting in
makeWrapper to double-quoting.
The tests now fail with the same problem as on master...

nixos/lib/testing.nix

@@ -113,14 +113,14 @@ rec {
             --add-flags "$vms" \
             ${lib.optionalString enableOCR "--prefix PATH : '${ocrProg}/bin'"} \
             --run "testScript=\"\$(cat $out/test-script)\"" \
-            --set testScript '"$testScript"' \
-            --set VLANS '"${toString vlans}"'
+            --set testScript '$testScript' \
+            --set VLANS '${toString vlans}'
           ln -s ${testDriver}/bin/nixos-test-driver $out/bin/nixos-run-vms
           wrapProgram $out/bin/nixos-run-vms \
             --add-flags "$vms" \
             ${lib.optionalString enableOCR "--prefix PATH : '${ocrProg}/bin'"} \
-            --set tests '"startAll; joinAll;"' \
-            --set VLANS '"${toString vlans}"' \
+            --set tests 'startAll; joinAll;' \
+            --set VLANS '${toString vlans}' \
             ${lib.optionalString (builtins.length vms == 1) "--set USE_SERIAL 1"}
         ''; # "
 

pkgs/build-support/setup-hooks/make-wrapper.sh

@@ -16,7 +16,7 @@ makeWrapper() {
             varName=${params[$((n + 1))]}
             value=${params[$((n + 2))]}
             n=$((n + 2))
-            echo "export $varName='$value'" >> $wrapper
+            echo "export $varName=\"$value\"" >> $wrapper
         fi
 
         if test "$p" = "--unset"; then