[tsan][test] Remove some unneded debug comments in a tsan test (#86896)

I introduced this test in #86537, let's remove some unneeded debugging
comments.
This PR was initially also moving the test to linux directory but looks
like it's already done by 17ab9e6 .

Author: canova

compiler-rt/test/tsan/Linux/signal_in_futex_wait.cpp

@@ -57,16 +57,13 @@ class Mutex {
 Mutex mutex;
 
 void *Thread(void *x) {
-  // fprintf(stderr, "canova here thread 0\n");
   // Waiting for the futex.
   mutex.lock();
-  // fprintf(stderr, "canova here thread 1\n");
   // Finished waiting.
   return nullptr;
 }
 
 static void SigprofHandler(int signal, siginfo_t *info, void *context) {
-  // fprintf(stderr, "canova here sigprof handler\n");
   // Unlock the futex.
   mutex.unlock();
 }