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/codegen/x86/X86/Gen.cc b/src/compiler/codegen/x86/X86/Gen.cc
index 6f33b56..c6cd55c 100644
--- a/src/compiler/codegen/x86/X86/Gen.cc
+++ b/src/compiler/codegen/x86/X86/Gen.cc
@@ -24,6 +24,12 @@
 
 namespace art {
 
+void genSpecialCase(CompilationUnit* cUnit, BasicBlock* bb, MIR* mir,
+                    SpecialCaseHandler specialCase)
+{
+    // TODO
+}
+
 /*
  * Perform register memory operation.
  */