drm-tests: Update common.mk with symbolic and visibility flags

This syncs common.mk with the latest source in src/platform2/common-mk.
Main change that affects the compiled binary are the newly added
-fvisibility-inlines-hidden CXXFLAGS and the -Bsymbolic-non-weak
LDFLAGS (see comments in the file for what these do).

Deviating from upstream, disable -Wimplicit-fallthrough and
-Wunreachable-code to unbreak compilation.

BUG=b:352469414
TEST=CQ

Change-Id: Ie2ee9c7638b6c56d2f42d55951987ab2d0c84765
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/drm-tests/+/5693545
Commit-Queue: Tatsuyuki Ishi <[email protected]>
Reviewed-by: Bas Nieuwenhuizen <[email protected]>
Auto-Submit: Tatsuyuki Ishi <[email protected]>
Tested-by: Tatsuyuki Ishi <[email protected]>
1 file changed