[Coroutines] Run coroutine passes by default

[Coroutines] Run coroutine passes by default

This patch make coroutine passes run by default in LLVM pipeline. Now
the clang and opt could handle IR inputs containing coroutine intrinsics
without special options.
It should be fine. On the one hand, the coroutine passes seems to be stable
since there are already many projects using coroutine feature.
On the other hand, the coroutine passes should do nothing for IR who doesn't
contain coroutine intrinsic.

Test Plan: check-llvm

Reviewed by: lxfind, aeubanks

Differential Revision: https://reviews.llvm.org/D105877