Add native memory accounting through custom allocator.

Added a custom allocator that lets you pass in a special tag which
specifices where the allocation came from. This is used when
dumping. The performance overhead is low since each allocation only
does a atomic add/sub for each allocation/free.

The measurements are dumped to traces.txt during SIGQUIT.

Example output:
I/art     (27274): AllocatorTagHeap active=120 max=120 total=168
I/art     (27274): AllocatorTagMonitorList active=1572 max=6240 total=11724
I/art     (27274): AllocatorTagClassTable active=185208 max=185208 total=268608
I/art     (27274): AllocatorTagInternTable active=430368 max=430368 total=436080
I/art     (27274): AllocatorTagMaps active=5616 max=6168 total=34392
I/art     (27274): AllocatorTagLOS active=1024 max=1536 total=2044
I/art     (27274): AllocatorTagSafeMap active=0 max=51936 total=533688
I/art     (27274): AllocatorTagLOSMaps active=144 max=1248 total=5760
I/art     (27274): AllocatorTagReferenceTable active=10944 max=11840 total=19136
I/art     (27274): AllocatorTagHeapBitmap active=32 max=40 total=56
I/art     (27274): AllocatorTagHeapBitmapLOS active=8 max=8 total=8
I/art     (27274): AllocatorTagVerifier active=0 max=18844 total=1073156
I/art     (27274): AllocatorTagModUnionCardSet active=5300 max=5920 total=56020
I/art     (27274): AllocatorTagModUnionReferenceArray active=24864 max=24864 total=24864
I/art     (27274): AllocatorTagJNILibrarires active=320 max=320 total=320
I/art     (27274): AllocatorTagOatFile active=1400 max=1400 total=5852

Change-Id: Ibb470ef2e9c9a24563bb46422d46a55799704d82

(cherry picked from commit 5369c40f75fdcb1be7a7c06db212ce965c83a164)
diff --git a/runtime/intern_table.h b/runtime/intern_table.h
index 435cc43..21f8046 100644
--- a/runtime/intern_table.h
+++ b/runtime/intern_table.h
@@ -19,6 +19,7 @@
 
 #include <map>
 
+#include "base/allocator.h"
 #include "base/mutex.h"
 #include "gc_root.h"
 #include "object_callbacks.h"
@@ -78,7 +79,8 @@
   void AllowNewInterns() SHARED_LOCKS_REQUIRED(Locks::mutator_lock_);
 
  private:
-  typedef std::multimap<int32_t, GcRoot<mirror::String>> Table;
+  typedef AllocationTrackingMultiMap<int32_t, GcRoot<mirror::String>,
+                                     kAllocatorTagInternTable> Table;
 
   mirror::String* Insert(mirror::String* s, bool is_strong)
       LOCKS_EXCLUDED(Locks::intern_table_lock_)