Force inlining on trivial accessors.

Make volatility for GetFieldObject a template parameter.
Move some trivial mirror::String routines to a -inl.h.

Bug: 14285442

Change-Id: Ie23b11d4f18cb15a62c3bbb42837a8aaf6b68f92
diff --git a/compiler/compiler.h b/compiler/compiler.h
index 1d5fc24..2357297 100644
--- a/compiler/compiler.h
+++ b/compiler/compiler.h
@@ -74,7 +74,8 @@
                                      uint32_t method_idx,
                                      const DexFile& dex_file) const = 0;
 
-  virtual uintptr_t GetEntryPointOf(mirror::ArtMethod* method) const = 0;
+  virtual uintptr_t GetEntryPointOf(mirror::ArtMethod* method) const
+     SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) = 0;
 
   virtual bool WriteElf(art::File* file,
                         OatWriter* oat_writer,