test: check for AbortController existence

Running tests comparitively on older versions of Node.js that
do not have AbortController can be a pain. Only add the
AbortController to knownGlobals if it actually exists.

Signed-off-by: James M Snell <jasnell@gmail.com>

PR-URL: #35616
Reviewed-By: Denys Otrishko <shishugi@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Richard Lau <rlau@redhat.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

test/common/index.js

@@ -253,7 +253,6 @@ function platformTimeout(ms) {
 }
 
 let knownGlobals = [
-  AbortController,
   clearImmediate,
   clearInterval,
   clearTimeout,
@@ -264,6 +263,15 @@ let knownGlobals = [
   queueMicrotask,
 ];
 
+// TODO(@jasnell): This check can be temporary. AbortController is
+// not currently supported in either Node.js 12 or 10, making it
+// difficult to run tests comparitively on those versions. Once
+// all supported versions have AbortController as a global, this
+// check can be removed and AbortController can be added to the
+// knownGlobals list above.
+if (global.AbortController)
+  knownGlobals.push(global.AbortController);
+
 if (global.gc) {
   knownGlobals.push(global.gc);
 }