Change grep pattern so it can report number of CppCompile actions correctly...

Change grep pattern so it can report number of CppCompile actions correctly without being impacted by setting -march on command line twice. am: 80f1ef15 am: a19e8ffd

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2406217



Change-Id: Ibfa072e786dacbc6cec0bbde4c7abec4f65f0f13
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>