Oilpan: remove now-unused thread affinity macros.

Explicit USED_FROM_MULTIPLE_THREADS*() declarations haven't been used for
some time; remove the unused macros.

R=haraken
BUG=420515

Review URL: https://codereview.chromium.org/674143002

git-svn-id: svn://svn.chromium.org/blink/trunk@184402 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Oilpan: widen Mac expectations for table-inflation-crash.html

TBR=oilpan-reviews,haraken
BUG=389648
NOTRY=true

Review URL: https://codereview.chromium.org/678873002

git-svn-id: svn://svn.chromium.org/blink/trunk@184403 bbb929c8-8fbe-4397-9dbb-9b2b20218538