MIPS: Make kAsciiDataHintTag have correct semantics for all both 1 and 2 byte string types.

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index f1f921fe8d8bbf63327071db31479d04543c1b7c..702a3b57408f6c4c75b424a421d9b4f6938e9754 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -6664,12 +6664,6 @@ void StringAddStub::Generate(MacroAssembler* masm) {
   __ and_(at, at, t1);
   __ Branch(&ascii_data, ne, at, Operand(zero_reg));
 
-  __ xor_(t0, t0, t1);
-  STATIC_ASSERT(kOneByteStringTag != 0 && kAsciiDataHintTag != 0);
-  __ And(t0, t0, Operand(kOneByteStringTag | kAsciiDataHintTag));
-  __ Branch(
-         &ascii_data, eq, t0, Operand(kOneByteStringTag | kAsciiDataHintTag));
-
   // Allocate a two byte cons string.
   __ AllocateTwoByteConsString(v0, t2, t0, t1, &call_runtime);
   __ Branch(&allocated);