sync: remove DEBUG_LOCKCONTENTION preprocessor directives

to allow logging the lock contentions without the need to define
DEBUG_LOCKCONTENTION at compile time.

src/sync.cpp

@@ -24,15 +24,10 @@
 #include <utility>
 #include <vector>
 
-#ifdef DEBUG_LOCKCONTENTION
-#if !defined(HAVE_THREAD_LOCAL)
-static_assert(false, "thread_local is not supported");
-#endif
 void LockContention(const char* pszName, const char* pszFile, int nLine)
 {
     LOG_TIME_MICROS_WITH_CATEGORY(strprintf("%s, %s:%d", pszName, pszFile, nLine), BCLog::LOCK);
 }
-#endif /* DEBUG_LOCKCONTENTION */
 
 #ifdef DEBUG_LOCKORDER
 //