feat: re-enable SpiderMonkey on macOS CI, bump to 128

Author: janl

build-aux/Jenkinsfile.full

@@ -125,8 +125,7 @@ meta = [
  // but works for the other workers.
  'macos': [
     name: 'macOS',
-    // spidermonkey_vsn: '91',
-    disable_spidermonkey: true, // tmp disable until SM>91 support lands
+    spidermonkey_vsn: '128',
     with_nouveau: false,
     with_clouseau: false,
     gnu_make: 'make'