Bug 1802605 - Use SpecialPowers.Services.env in gfx tests r=botond

Differential Revision: https://phabricator.services.mozilla.com/D163249

gfx/layers/apz/test/mochitest/helper_relative_scroll_smoothness.html

@@ -121,7 +121,7 @@ async function test() {
 }
 
 function isOnChaosMode() {
-  return Services.env.get("MOZ_CHAOSMODE");
+  return SpecialPowers.Services.env.get("MOZ_CHAOSMODE");
 }
 
 if (searchParams.get("input-type") == "native-key" &&

gfx/layers/apz/test/mochitest/helper_transform_end_on_keyboard_scroll.html

@@ -42,12 +42,7 @@ async function test() {
 }
 
 function isOnChaosMode() {
-  // TODO (barret): bug 1802605 - Using SpecialPowers.Services.env causes test
-  // time outs on macOS.
-  // eslint-disable-next-line mozilla/use-services
-  const env = SpecialPowers.Cc["@mozilla.org/process/environment;1"]
-                           .getService(SpecialPowers.Ci.nsIEnvironment);
-  return env.get("MOZ_CHAOSMODE");
+  return SpecialPowers.Services.env.get("MOZ_CHAOSMODE");
 }
 
 if ((getPlatform() == "mac" || getPlatform() == "windows") &&