Revert "ART: Start RuntimeCallbacks"

jdwp tests failing with:
    STDERR> dalvikvm32 E 01-18 23:14:50 12180 12198 thread-inl.h:137] holding "runtime callbacks lock" at point where thread suspension is expected

Bug: 31684920

This reverts commit 13093d455b8266338fd713b04261c58e9dc2b164.

Change-Id: I94e4154e273d006eecdd485607dcfd96392d6a00
diff --git a/runtime/base/mutex.h b/runtime/base/mutex.h
index e44bdb8..2adeb8c 100644
--- a/runtime/base/mutex.h
+++ b/runtime/base/mutex.h
@@ -111,7 +111,6 @@
   kJdwpEventListLock,
   kJdwpAttachLock,
   kJdwpStartLock,
-  kRuntimeCallbacksLock,
   kRuntimeShutdownLock,
   kTraceLock,
   kHeapBitmapLock,
@@ -616,11 +615,8 @@
   // Guards shutdown of the runtime.
   static Mutex* runtime_shutdown_lock_ ACQUIRED_AFTER(heap_bitmap_lock_);
 
-  // Guards accesses to runtime callback lists.
-  static ReaderWriterMutex* runtime_callbacks_lock_ ACQUIRED_AFTER(runtime_shutdown_lock_);
-
   // Guards background profiler global state.
-  static Mutex* profiler_lock_ ACQUIRED_AFTER(runtime_callbacks_lock_);
+  static Mutex* profiler_lock_ ACQUIRED_AFTER(runtime_shutdown_lock_);
 
   // Guards trace (ie traceview) requests.
   static Mutex* trace_lock_ ACQUIRED_AFTER(profiler_lock_);