ART: Clean up field initialization

Add explicit field initialization to default value where necessary.
Also clean up interpreter intrinsics header.

Test: m
Change-Id: I7a850ac30dcccfb523a5569fb8400b9ac892c8e5
diff --git a/runtime/stack_map.h b/runtime/stack_map.h
index ffa17c9..a224986 100644
--- a/runtime/stack_map.h
+++ b/runtime/stack_map.h
@@ -688,7 +688,13 @@
 
 class StackMapEncoding {
  public:
-  StackMapEncoding() {}
+  StackMapEncoding()
+      : dex_pc_bit_offset_(0),
+        dex_register_map_bit_offset_(0),
+        inline_info_bit_offset_(0),
+        register_mask_index_bit_offset_(0),
+        stack_mask_index_bit_offset_(0),
+        total_bit_size_(0) {}
 
   // Set stack map bit layout based on given sizes.
   // Returns the size of stack map in bits.