sanitizer_common: revert StaticSpinMutex ctor

[dvyukov]

Summary

Patch "sanitizer_common: modernize SpinMutex" added default
ctor to StaticSpinMutex. But it broke some gcc bots with:

scudo_tsd_exclusive.cpp:25:22: error: non-local variable
‘scudo::TSD’ declared ‘thread’ needs dynamic initialization

https://lab.llvm.org/buildbot/#/builders/105/builds/12649

Unfortunatly none of empty ctor {}, no ctor, default constexpr ctor
work for different reasons. So remove StaticSpinMutex ctor
entirely and move deleted copy ctor back to SpinMutex.

compiler-rt/lib/sanitizer_common/sanitizer_mutex.h

 #include "sanitizer_internal_defs.h"
 #include "sanitizer_libc.h"
 #include "sanitizer_thread_safety.h"
 
 namespace __sanitizer {
 
 class MUTEX StaticSpinMutex {
  public:
-  StaticSpinMutex() = default;
-
   void Init() {
     atomic_store(&state_, 0, memory_order_relaxed);
   }
 
   void Lock() ACQUIRE() {
     if (LIKELY(TryLock()))
       return;
     LockSlow();
   }
 
   bool TryLock() TRY_ACQUIRE(true) {
     return atomic_exchange(&state_, 1, memory_order_acquire) == 0;
   }
 
   void Unlock() RELEASE() { atomic_store(&state_, 0, memory_order_release); }
 
   void CheckLocked() const CHECK_LOCKED() {
     CHECK_EQ(atomic_load(&state_, memory_order_relaxed), 1);
   }
 
  private:
   atomic_uint8_t state_;
 
   void LockSlow();
-
-  StaticSpinMutex(const StaticSpinMutex &) = delete;
-  void operator=(const StaticSpinMutex &) = delete;
 };
 
 class MUTEX SpinMutex : public StaticSpinMutex {
  public:
   SpinMutex() {
     Init();
   }
+
+  SpinMutex(const SpinMutex &) = delete;
+  void operator=(const SpinMutex &) = delete;
 };
 
 // Semaphore provides an OS-dependent way to park/unpark threads.
 // The last thread returned from Wait can destroy the object
 // (destruction-safety).
 class Semaphore {
  public:
   constexpr Semaphore() {}