Remove ArtMethod* parameter from dex cache entry points.

Load the ArtMethod* using an optimized stack walk instead.
This reduces the size of the generated code.

Three of the entry points are called only from a slow-path
and the fourth (InitializeTypeAndVerifyAccess) is rare and
already slow enough that the one or two extra loads
(depending on whether we already have the ArtMethod* in a
register) are insignificant. And as we're starting to use
PC-relative addressing of the dex cache arrays (already
done by Quick for the boot image), having the ArtMethod* in
a register becomes less likely anyway.

Change-Id: Ib19b9d204e355e13bf386662a8b158178bf8ad28
diff --git a/compiler/dex/quick/mir_to_lir.h b/compiler/dex/quick/mir_to_lir.h
index 8f08a51..6f227fc 100644
--- a/compiler/dex/quick/mir_to_lir.h
+++ b/compiler/dex/quick/mir_to_lir.h
@@ -1692,10 +1692,8 @@
      * @param r_result the result register.
      * @param trampoline the helper to call in slow path.
      * @param imm the immediate passed to the helper.
-     * @param r_method the register with ArtMethod* if available, otherwise RegStorage::Invalid().
      */
-    void GenIfNullUseHelperImmMethod(
-        RegStorage r_result, QuickEntrypointEnum trampoline, int imm, RegStorage r_method);
+    void GenIfNullUseHelperImm(RegStorage r_result, QuickEntrypointEnum trampoline, int imm);
 
     /**
      * @brief Generate code to retrieve Class* for another type to be used by SGET/SPUT.