add tests for _Utils_eqHelp

[jerith666]

do non-recursive tests before the depth check. this ensures that the 'for(key in x)' loop properly short-circuits, and avoids putting Tuple2s containing 'undefined' on the stack.

fixes #1011; see that issue and #1031 for further discussion

listTests by @Skinney

[jerith666]

Now that #1031 has been merged, all that's left here are the additional tests. I've resolved the conflict in case you want to include them.