[mips] Fix MIPS/MIPS64 test failures after r31120.

TBR=machenbach@chromium.org

Review URL: https://codereview.chromium.org/1377643003 .

Cr-Commit-Position: refs/heads/master@{#31121}

src/mips/builtins-mips.cc

@@ -58,7 +58,7 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   __ lw(a2,
         FieldMemOperand(a2, SharedFunctionInfo::kFormalParameterCountOffset));
   __ SmiUntag(a2);
-  __ Branch(&argc, ne, a2,
+  __ Branch(&argc, eq, a2,
             Operand(SharedFunctionInfo::kDontAdaptArgumentsSentinel));
   __ Addu(a0, a2, num_extra_args + 1);
   __ jmp(&done_argc);

src/mips64/builtins-mips64.cc

@@ -56,7 +56,7 @@ void Builtins::Generate_Adaptor(MacroAssembler* masm,
   __ ld(a2, FieldMemOperand(a1, JSFunction::kSharedFunctionInfoOffset));
   __ lw(a2,
         FieldMemOperand(a2, SharedFunctionInfo::kFormalParameterCountOffset));
-  __ Branch(&argc, ne, a2,
+  __ Branch(&argc, eq, a2,
             Operand(SharedFunctionInfo::kDontAdaptArgumentsSentinel));
   __ Daddu(a0, a2, num_extra_args + 1);
   __ jmp(&done_argc);