[tsan] Add support for GCD dispatch_suspend and dispatch_resume

GCD queues can be suspended and resumed with dispatch_suspend and dispatch_resume. We need to add synchronization between the call to dispatch_resume and any subsequent executions of blocks in the queue that was resumed. We already have an Acquire(q) before the block executes, so this patch just adds the Release(q) in an interceptor of dispatch_resume.

Differential Revision: https://reviews.llvm.org/D27112

llvm-svn: 287902