refactor(ngMock window.inject test): comment on important function wrapper usage

Explicitly commented on why we use an extra function wrapper around the
test inject Error throwing code, and how not using it would make our
tests give us false positives on certain browsers, e.g. Firefox.

Author: jurko-gospodnetic

test/ngMock/angular-mocksSpec.js

@@ -939,6 +939,9 @@ describe('ngMock', function() {
       // call in multiple test specs
       function testInjectCaller() {
         var shouldThrow;
+        // using an extra internalInjectCaller() wrapper here avoids stack trace
+        // constructed by some browsers (e.g. FireFox) from containing the name
+        // of the external caller function
         var injectingCall = (function internalInjectCaller() {
           return inject(function() {
             if (shouldThrow)