The opt level (O2 versus Om1) should be tested using Cfg::getOptLevel() instead of getFlags().getOptLevel() whenever possible.

This is because if you run "-Om1 -force-O2=foo", and you're compiling foo, the first form tells you O2 while the second form tells you Om1.

BUG= none
R=eholk@chromium.org

Review URL: https://codereview.chromium.org/2210773002 .