Implement double and float support for arm in register allocator.

The basic approach is:
- An instruction that needs two registers gets two intervals.
- When allocating the low part, we also allocate the high part.
- When splitting a low (or high) interval, we also split the high
  (or low) equivalent.
- Allocation follows the (S/D register) requirement that low
  registers are always even and the high equivalent is low + 1.

Change-Id: I06a5148e05a2ffc7e7555d08e871ed007b4c2797
diff --git a/compiler/optimizing/code_generator.cc b/compiler/optimizing/code_generator.cc
index 4d8154e..ada0fb7 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -620,6 +620,14 @@
         break;
       }
 
+      case Location::kFpuRegisterPair : {
+        stack_map_stream_.AddDexRegisterEntry(DexRegisterMap::kInFpuRegister, location.low());
+        stack_map_stream_.AddDexRegisterEntry(DexRegisterMap::kInFpuRegister, location.high());
+        ++i;
+        DCHECK_LT(i, environment_size);
+        break;
+      }
+
       default:
         LOG(FATAL) << "Unexpected kind " << location.GetKind();
     }