Cleanup TestExpectations for a bunch of inspector/tracing tests

Most of them stopped being flakey, a bunch of remaining ones should
get better after https://codereview.chromium.org/626483004

TBR=yurys

Review URL: https://codereview.chromium.org/621753005

git-svn-id: svn://svn.chromium.org/blink/trunk@183146 bbb929c8-8fbe-4397-9dbb-9b2b20218538