Unify ART's various implementations of bit_cast.

ART had several implementations of art::bit_cast:

1. one in runtime/base/casts.h, declared as:

   template <class Dest, class Source>
   inline Dest bit_cast(const Source& source);

2. another one in runtime/utils.h, declared as:

   template<typename U, typename V>
   static inline V bit_cast(U in);

3. and a third local version, in runtime/memory_region.h,
   similar to the previous one:

   template<typename Source, typename Destination>
   static Destination MemoryRegion::local_bit_cast(Source in);

This CL removes versions 2. and 3. and changes their callers
to use 1. instead.  That version was chosen over the others
as:
- it was the oldest one in the code base; and
- its syntax was closer to the standard C++ cast operators,
  as it supports the following use:

    bit_cast<Destination>(source)

  since `Source' can be deduced from `source'.

Change-Id: I7334fd5d55bf0b8a0c52cb33cfbae6894ff83633
diff --git a/runtime/interpreter/unstarted_runtime.cc b/runtime/interpreter/unstarted_runtime.cc
index fbbc863..98dfdbd 100644
--- a/runtime/interpreter/unstarted_runtime.cc
+++ b/runtime/interpreter/unstarted_runtime.cc
@@ -460,7 +460,7 @@
 static void UnstartedDoubleDoubleToRawLongBits(
     Thread* self ATTRIBUTE_UNUSED, ShadowFrame* shadow_frame, JValue* result, size_t arg_offset) {
   double in = shadow_frame->GetVRegDouble(arg_offset);
-  result->SetJ(bit_cast<int64_t>(in));
+  result->SetJ(bit_cast<int64_t, double>(in));
 }
 
 static mirror::Object* GetDexFromDexCache(Thread* self, mirror::DexCache* dex_cache)