Ensure VM's heap is accounted correctly.

The meminfo dumping assumes that dalvik heap is created using ashmem and has a
prefix of "dalvik-". Ensure ART's anonymous mmaps fit this pattern. Tidy up
anonymous mmaps so naming is more consistent.

Change-Id: I9c62a9d1da21da6a048effb0399a1f85865cb12d
diff --git a/src/gc/large_object_space.cc b/src/gc/large_object_space.cc
index 69320fa..a589e67 100644
--- a/src/gc/large_object_space.cc
+++ b/src/gc/large_object_space.cc
@@ -60,7 +60,8 @@
 }
 
 mirror::Object* LargeObjectMapSpace::Alloc(Thread* self, size_t num_bytes) {
-  MemMap* mem_map = MemMap::MapAnonymous("allocation", NULL, num_bytes, PROT_READ | PROT_WRITE);
+  MemMap* mem_map = MemMap::MapAnonymous("large object space allocation", NULL, num_bytes,
+                                         PROT_READ | PROT_WRITE);
   if (mem_map == NULL) {
     return NULL;
   }