Use direct class pointers at allocation sites in the compiled code.

- Rather than looking up a class from its type ID (and checking if
  it's resolved/initialized, resolving/initializing if not), use
  direct class pointers, if possible (boot-code-to-boot-class pointers
  and app-code-to-boot-class pointers.)
- This results in a 1-2% speedup in Ritz MemAllocTest on Nexus 4.
- Embedding the object size (along with class pointers) caused a 1-2%
  slowdown in MemAllocTest and isn't implemented in this change.
- TODO: do the same for array allocations.
- TODO: when/if an application gets its own image, implement
  app-code-to-app-class pointers.
- Fix a -XX:gc bug.
  cf. https://android-review.googlesource.com/79460/
- Add /tmp/android-data/dalvik-cache to the list of locations to
  remove oat files in clean-oat-host.
  cf. https://android-review.googlesource.com/79550
- Add back a dropped UNLIKELY in FindMethodFromCode().
  cf. https://android-review.googlesource.com/74205

Bug: 9986565
Change-Id: I590b96bd21f7a7472f88e36752e675547559a5b1
diff --git a/runtime/globals.h b/runtime/globals.h
index a0d7e48..b1ccbdc 100644
--- a/runtime/globals.h
+++ b/runtime/globals.h
@@ -88,6 +88,10 @@
 // True if we allow moving methods.
 static constexpr bool kMovingMethods = false;
 
+// If true, the quick compiler embeds class pointers in the compiled
+// code, if possible.
+static constexpr bool kEmbedClassInCode = true;
+
 }  // namespace art
 
 #endif  // ART_RUNTIME_GLOBALS_H_