Revert workarounds for Clang coroutines bugs in tests
Revert workarounds for Clang coroutines bugs in tests

Summary:
The CoroTest.cpp file had some tests that were failing under Clang optimised builds due to a compiler bug.

This rolls back those work arounds to re-expose the bug as a way of validating that the bug has been fixed.

Reviewed By: tks2103

Differential Revision: D13383774

fbshipit-source-id: ac219c6ed0a0c8c3b8c3c06e3d01e5ed4ade81bc

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