Custom codegen for small frameless methods.

Added a general mechanism that will allow pattern matching of
small methods and (generally) frameless code generation.  Prevously,
all frames were at least 16 bytes, not you can have zero-length
frames (and thus some old asserts had to go).

Change-Id: Ic786940a602e25b48cbc317ac601ac84cc307762
diff --git a/src/compiler/Compiler.h b/src/compiler/Compiler.h
index 238e3ff..4b4e83d 100644
--- a/src/compiler/Compiler.h
+++ b/src/compiler/Compiler.h
@@ -51,6 +51,7 @@
     kSkipLargeMethodOptimization,
     kSafeOptimizations,
     kBBOpt,
+    kMatch,
     kPromoteCompilerTemps,
 };