Fix build breakage

Remove #warning compilation messages for no longer used flags.

Bug: 230576679
Test: builds adt3/yukawa and runs presubmit.
Ignore-AOSP-First: cherry-pick from aosp/2077499

Change-Id: I85610dc0464bc1b1d9b84529611e385a36720276
Merged-In: I85610dc0464bc1b1d9b84529611e385a36720276