Remove test for -fcoroutines-ts

After clang update, we got the below error:
  external/libcxx/libcxx_test_template.cpp
  clang++: error: unknown argument: '-fcoroutines-ts'

Since this option has been removed in clang, remove test for it.

Bug: 280683256
Test: build with clang-r498229
Change-Id: Icecd7152f8d724d680bf17e3f920f15365b285a6
2 files changed