Prevent some compiler optimizations

[accelerated]

Describe your changes

• Fix compiler optimizations and minor bugs caused by using -03
• Updated travis to build with RelWithDebInfo instead of Debug

Notable bugs found

• On quantum_spinlock_util_impl.h:329 in spinWaitWriter() the closing parenthesis was in the wrong place.
• In lockRead, lockWrite and upgradeToWriteImpl the check for spinWaitReader and spinWaitWriter was checking against != Attempt::Once instead of ==Attempt::Unlimited. When upgrading coroutines to write, the attempt is set to Attempt::Reentrant which was causing the coroutine to enter this spinwait loop. Since this spin wait loop does not yield the coroutine, the first coroutine being upgraded would take the lock, waiting for all other coroutine readers to either upgrade or release their read locks. However since all other coroutines could never run (because of the non-yield) this would result in a deadlock. Previous upgradeToWrite tests only involved scenarios with threads which did not have this problem. A different test using coroutines is now added to check proper behavior in both cases.

Signed-off-by: Alexander Damian adamian@bloomberg.net

Testing performed

• Added more tests for coroutine synchronization for ReadWriteLocks.

[arosenzweig3]

Looks good to me.