ART: Refactor CommonRuntimeTest::SetUp

Factor out finishing up the runtime. This code will execute the
interpreter to initialize important classes etc., which is not
necessary for testing RuntimeMethod sizes and trampoline entrypoints,
in fact it may violate pointer-size invariants.

Also add InstructionSet parsing tests to the ParsedOptions test.

Change-Id: I75cd00c6d358e1bc962c8f1845244f6400c1cd6c
diff --git a/runtime/common_runtime_test.h b/runtime/common_runtime_test.h
index 6da2bef..f318457 100644
--- a/runtime/common_runtime_test.h
+++ b/runtime/common_runtime_test.h
@@ -114,6 +114,10 @@
   // Called after the runtime is created.
   virtual void PostRuntimeCreate() {}
 
+  // Called to finish up runtime creation and filling test fields. By default runs root
+  // initializers, initialize well-known classes, and creates the heap thread pool.
+  virtual void FinalizeSetup();
+
   // Gets the path of the specified dex file for host or target.
   static std::string GetDexFileName(const std::string& jar_prefix);