Fast path interface dispatch.

Interface dispatch when the method we're dispatching against is known
currently goes slow path. This change makes the load of the interface
method either a load of a constant or from the resolve methods table. It
also makes the null check on the "this" pointer inline.

Change-Id: I69571a062d3d693bee2dec6e46a456e0f74411cd
diff --git a/src/compiler/codegen/MethodCodegenDriver.cc b/src/compiler/codegen/MethodCodegenDriver.cc
index 3a80d10..3321c33 100644
--- a/src/compiler/codegen/MethodCodegenDriver.cc
+++ b/src/compiler/codegen/MethodCodegenDriver.cc
@@ -83,8 +83,11 @@
                                        directMethod)
     && !SLOW_INVOKE_PATH;
   if (info->type == kInterface) {
+    if (fastPath) {
+      pNullCk = &nullCk;
+    }
     nextCallInsn = fastPath ? nextInterfaceCallInsn
-        : nextInterfaceCallInsnWithAccessCheck;
+                            : nextInterfaceCallInsnWithAccessCheck;
     skipThis = false;
   } else if (info->type == kDirect) {
     if (fastPath) {