adb: Don't force -O2

Don't force -O2 over -O3 -- the O2 hardcode is there to force
optimizations, not to reduce them...

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
sync_test: Use -fno-strict-aliasing

Use -fno-strict-aliasing here so we don't have to use it globally.
Performance on tests isn't important anyway.

Change-Id: I92ae7209ced60176cc5608f32b8ff6a911c09f10
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>