Move ArtField to native

Add linear alloc. Moved ArtField to be native object. Changed image
writer to put ArtFields after the mirror section.

Savings:
2MB on low ram devices
4MB on normal devices

Total PSS measurements before (normal N5, 95s after shell start):
Image size: 7729152 bytes
23112 kB: .NonMoving
23212 kB: .NonMoving
22868 kB: .NonMoving
23072 kB: .NonMoving
22836 kB: .NonMoving
19618 kB: .Zygote
19850 kB: .Zygote
19623 kB: .Zygote
19924 kB: .Zygote
19612 kB: .Zygote
Avg: 42745.4 kB

After:
Image size: 7462912 bytes
17440 kB: .NonMoving
16776 kB: .NonMoving
16804 kB: .NonMoving
17812 kB: .NonMoving
16820 kB: .NonMoving
18788 kB: .Zygote
18856 kB: .Zygote
19064 kB: .Zygote
18841 kB: .Zygote
18629 kB: .Zygote
3499 kB: .LinearAlloc
3408 kB: .LinearAlloc
3424 kB: .LinearAlloc
3600 kB: .LinearAlloc
3436 kB: .LinearAlloc
Avg: 39439.4 kB

No reflection performance changes.

Bug: 19264997
Bug: 17643507

Change-Id: I10c73a37913332080aeb978c7c94713bdfe4fe1c
diff --git a/runtime/primitive.h b/runtime/primitive.h
index 32bfdaf..3818487 100644
--- a/runtime/primitive.h
+++ b/runtime/primitive.h
@@ -27,21 +27,11 @@
 static constexpr size_t kObjectReferenceSize = 4;
 
 
-template<size_t kComponentSize>
-size_t ComponentSizeShiftWidth() {
-  switch (kComponentSize) {
-    case 1:
-      return 0U;
-    case 2:
-      return 1U;
-    case 4:
-      return 2U;
-    case 8:
-      return 3U;
-    default:
-      LOG(FATAL) << "Unexpected component size : " << kComponentSize;
-      return 0U;
-  }
+constexpr size_t ComponentSizeShiftWidth(size_t component_size) {
+  return component_size == 1u ? 0u :
+      component_size == 2u ? 1u :
+          component_size == 4u ? 2u :
+              component_size == 8u ? 3u : 0u;
 }
 
 class Primitive {
@@ -95,7 +85,7 @@
       case kPrimFloat:   return 2;
       case kPrimLong:
       case kPrimDouble:  return 3;
-      case kPrimNot:     return ComponentSizeShiftWidth<kObjectReferenceSize>();
+      case kPrimNot:     return ComponentSizeShiftWidth(kObjectReferenceSize);
       default:
         LOG(FATAL) << "Invalid type " << static_cast<int>(type);
         return 0;