yank out shared mutex impl

Initially shared mutex was needed to lock cores so thread pool
executes one parallel for at a time but on machine with high core count
we cant saturate processor all the time so we switched to shared semaphore
and block thread when all cores are busy.

src/os/core/win32/os_core_win32.c

@@ -1106,40 +1106,6 @@ os_mutex_drop(OS_Handle mutex)
   LeaveCriticalSection(&entity->mutex);
 }
 
-internal OS_Handle
-os_shared_mutex_alloc(String8 name)
-{
-  Assert(name.size);
-  Temp scratch = scratch_begin(0,0);
-  String16 name16 = str16_from_8(scratch.arena, name);
-  HANDLE handle = CreateMutexW(0, 0, (WCHAR*)name16.str);
-  Assert(handle != 0);
-  OS_Handle mutex = {(U64)handle};
-  scratch_end(scratch);
-  return mutex;
-}
-
-internal void
-os_shared_mutex_release(OS_Handle mutex)
-{
-  CloseHandle((HANDLE)mutex.u64[0]);
-}
-
-internal B32
-os_shared_mutex_take(OS_Handle mutex, U64 endt_us)
-{
-  U32 sleep_ms = os_w32_sleep_ms_from_endt_us(endt_us);
-  DWORD wait_result = WaitForSingleObject((HANDLE)mutex.u64[0], sleep_ms);
-  B32 result = (wait_result == WAIT_OBJECT_0);
-  return result;
-}
-
-internal void
-os_shared_mutex_drop(OS_Handle mutex)
-{
-  ReleaseMutex((HANDLE)mutex.u64[0]);
-}
-
 //- rjf: reader/writer mutexes
 
 internal OS_Handle