dex2oat: add --cpu-set command-line option

Enables affinitizing dex2oat threads to a specific group of CPUs.

Bug: 141446571
Bug: 149395059
Test: art/test/run-test -Xcompiler-option --cpu-set=0,1 956
Test: art/test/run-test -Xcompiler-option --cpu-set=,0,1 956
Test: art/test/run-test -Xcompiler-option --cpu-set=,, 956
Test: art/test/run-test -Xcompiler-option --cpu-set=0,a 956
Test: cmdline_parser_test
Change-Id: I4bb1519beacd329da1a69af31982a6154d315865
Merged-In: I4bb1519beacd329da1a69af31982a6154d315865
(cherry picked from commit ffc791c748dd28cc6bc7fff825b3c1b7af96abb3)