Fix TSAN build and re-enable the tests (#7386)
Summary:
Resolve TSAN build warnings and re-enable disabled TSAN tests.
Not sure if it's a compiler issue or TSAN check issue. Switching from
conditional operator to if-else mitigated the problem.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7386
Test Plan:
run TSAN check 10 times in circleci.
```
WARNING: ThreadSanitizer: data race (pid=27735)
Atomic write of size 8 at 0x7b54000005e8 by thread T32:
#0 __tsan_atomic64_store <null> (db_test+0x4cee95)
https://github.com/facebook/rocksdb/issues/1 std::__atomic_base<unsigned long>::store(unsigned long, std::memory_order) /usr/bin/../lib/gcc/x86_64-linux-gnu/5.4.0/../../../../include/c++/5.4.0/bits/atomic_base.h:374:2 (db_test+0x78460e)
https://github.com/facebook/rocksdb/issues/2 rocksdb::VersionSet::SetLastSequence(unsigned long) /home/circleci/project/./db/version_set.h:1058:20 (db_test+0x78460e)
...
Previous read of size 8 at 0x7b54000005e8 by thread T31:
#0 bool rocksdb::DBImpl::MultiCFSnapshot<std::unordered_map<unsigned int, rocksdb::DBImpl::MultiGetColumnFamilyData, std::hash<unsigned int>, std::equal_to<unsigned int>, std::allocator<std::pair<unsigned int const, rocksdb::DBImpl::MultiGetColumnFamilyData> > > >(rocksdb::ReadOptions const&, rocksdb::ReadCallback*, std::function<rocksdb::DBImpl::MultiGetColumnFamilyData* (std::unordered_map<unsigned int, rocksdb::DBImpl::MultiGetColumnFamilyData, std::hash<unsigned int>, std::equal_to<unsigned int>, std::allocator<std::pair<unsigned int const, rocksdb::DBImpl::MultiGetColumnFamilyData> > >::iterator&)>&, std::unordered_map<unsigned int, rocksdb::DBImpl::MultiGetColumnFamilyData, std::hash<unsigned int>, std::equal_to<unsigned int>, std::allocator<std::pair<unsigned int const, rocksdb::DBImpl::MultiGetColumnFamilyData> > >*, unsigned long*) /home/circleci/project/db/db_impl/db_impl.cc (db_test+0x715087)
```
Reviewed By: ltamasi
Differential Revision: D23725226
Pulled By: jay-zhuang
fbshipit-source-id: a6d662a5ea68111246cd32ec95f3411a25f76bc6
fa92b9dc9f