Remove test for -fcoroutines-ts am: 4b737c774c

Original change: https://android-review.googlesource.com/c/platform/external/libcxx/+/2620093

Change-Id: I5a9304f0a476e3e5bac27506c2f625cab2c35aa2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>