SWDEV-306410 - Remove program lock

Remove global program lock in order to fix too
long kernel launch overhead with multi-threads
on MGPUs.
This patch depends on a compiler patch that makes
LC thread safe.
Change-Id: Ic8a7374d19112764d6de5d483ec5d07a56661d1b

rocclr/platform/program.hpp

@@ -126,9 +126,6 @@ class Program : public RuntimeObject {
   //! Clears the program object if the app attempts to rebuild the program
   void clear();
 
-  //! Global build lock (remove when LLVM is thread-safe).
-  static Monitor buildLock_;
-
  public:
   //! Construct a new program to be compiled from the given source code.
   Program(Context& context, const std::string& sourceCode, Language language,