MIPS: Improve '[es6] When comparing two symbols we may need to throw a TypeError'.

Improve d26f5d39

Original commit message:
When comparing a symbol to istself using <, <=, > or >= we need to
throw a TypeError. This is correctly handled in the runtime function
so if we are comparing a symbol fall back to use the runtime.

BUG=

Review URL: https://codereview.chromium.org/1124863004

Cr-Commit-Position: refs/heads/master@{#28240}

src/mips/code-stubs-mips.cc

@@ -294,7 +294,6 @@ static void EmitIdenticalObjectComparison(MacroAssembler* masm,
   if (cc == less || cc == greater) {
     __ GetObjectType(a0, t4, t4);
     __ Branch(slow, greater, t4, Operand(FIRST_SPEC_OBJECT_TYPE));
-    __ GetObjectType(a0, t4, t4);
     __ Branch(slow, eq, t4, Operand(SYMBOL_TYPE));
   } else {
     __ GetObjectType(a0, t4, t4);

src/mips64/code-stubs-mips64.cc

@@ -290,7 +290,6 @@ static void EmitIdenticalObjectComparison(MacroAssembler* masm,
   if (cc == less || cc == greater) {
     __ GetObjectType(a0, t0, t0);
     __ Branch(slow, greater, t0, Operand(FIRST_SPEC_OBJECT_TYPE));
-    __ GetObjectType(a0, t0, t0);
     __ Branch(slow, eq, t0, Operand(SYMBOL_TYPE));
   } else {
     __ GetObjectType(a0, t0, t0);