tsan: refactor storage of meta information for heap blocks and sync objects
The new storage (MetaMap) is based on direct shadow (instead of a hashmap + per-block lists).
This solves a number of problems:
 - eliminates quadratic behaviour in SyncTab::GetAndLock (https://code.google.com/p/thread-sanitizer/issues/detail?id=26)
 - eliminates contention in SyncTab
 - eliminates contention in internal allocator during allocation of sync objects
 - removes a bunch of ad-hoc code in java interface
 - reduces java shadow from 2x to 1/2x
 - allows to memorize heap block meta info for Java and Go
 - allows to cleanup sync object meta info for Go
 - which in turn enabled deadlock detector for Go




git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@209810 91177308-0d34-0410-b5e6-96231b3b80d8