Import final sdk version 31 from build 7511229

Note that this is a re-finalization of API 31, following some updates
to the internal API between the platform and ART.

The coreplatform files are now removed as they are identical to the
module-lib API.

Bug: 192227286
Test: presubmit
Change-Id: I939a782ef8e39b2f0590d8c2d31690a9c95e1cba
108 files changed