[lldb][Widows] Remove unused WriteTryLock function

Unused since d792094c26.

[2571/6469] Building CXX object tools/lldb/sourc...iles/lldbHost.dir/windows/ProcessRunLock.cpp.obj
C:/Users/tcwg/llvm-worker/lldb-aarch64-windows/llvm-project/lldb/source/Host/windows/ProcessRunLock.cpp(31,13): warning: unused function 'WriteTryLock' [-Wunused-function]
   31 | static bool WriteTryLock(lldb::rwlock_t rwlock) {
      |             ^~~~~~~~~~~~
1 warning generated.

lldb/source/Host/windows/ProcessRunLock.cpp

@@ -28,10 +28,6 @@ static bool WriteLock(lldb::rwlock_t rwlock) {
   return true;
 }
 
-static bool WriteTryLock(lldb::rwlock_t rwlock) {
-  return !!::TryAcquireSRWLockExclusive(GetLock(rwlock));
-}
-
 static bool WriteUnlock(lldb::rwlock_t rwlock) {
   ::ReleaseSRWLockExclusive(GetLock(rwlock));
   return true;