Add "//build/config/compiler:optimize_max" to rtc_add_configs and
"//build/config/compiler:default_optimization" to rtc_remove_configs.
This is the default optimization in GYP, and might help explain a 82.5%
regression in webrtc_perf_tests at 13946:13946
BUG=chromium:641966
NOTRY=True
Review-Url: https://codereview.webrtc.org/2307283002
Cr-Commit-Position: refs/heads/master@{#14067}