8161258: Simplify including platform files

Include patform files with macros cpu_header() etc. Do various cleanups of macro usages. Remove _64/_32 from adlc generated files and platform .hpp files. Merge stubRoutines_x86*.hpp. Remove empty mutex_<os>* files.

Reviewed-by: dholmes, coleenp, kbarrett

hotspot/src/share/vm/runtime/os.cpp

@@ -1742,7 +1742,7 @@ void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
   pd_realign_memory(addr, bytes, alignment_hint);
 }
 
-#ifndef TARGET_OS_FAMILY_windows
+#ifndef _WINDOWS
 /* try to switch state from state "from" to state "to"
  * returns the state set after the method is complete
  */