remove all uses of our custom spinlock

This has caused issues and over time we have reduced the use of 
spinlocks, it was only used in few places and we still have evidence
that it's causing ANRs.

We use utils::Mutex instead which is a low overhead mutex implementation
on Linux systems.

FIXES=[321101014]

libs/utils/include/utils/JobSystem.h

@@ -387,7 +387,7 @@ private:
     uint8_t mParallelSplitCount = 0;                    // # of split allowable in parallel_for
     Job* mRootJob = nullptr;
 
-    utils::SpinLock mThreadMapLock; // this should have very little contention
+    utils::Mutex mThreadMapLock; // this should have very little contention
     tsl::robin_map<std::thread::id, ThreadState *> mThreadMap;
 };