Ensure that we do not accidentally emit debug code.

src/mips/lithium-codegen-mips.cc

Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc b/src/mips/lithium-codegen-mips.cc
index 4ad12eb42373a5c2abbf0e4305830289646e1c91..6488285c3b16ff4861d3c3b3d8d45524d1ad908a 100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -2004,7 +2004,7 @@ void LCodeGen::DoGetCachedArrayIndex(LGetCachedArrayIndex* instr) {
   Register input = ToRegister(instr->value());
   Register result = ToRegister(instr->result());
 
-  __ AbortIfNotString(input);
+  __ AssertString(input);
 
   __ lw(result, FieldMemOperand(input, String::kHashFieldOffset));
   __ IndexFromHash(result, result);
@@ -4028,9 +4028,7 @@ void LCodeGen::DoDeferredStringCharCodeAt(LStringCharCodeAt* instr) {
     __ push(index);
   }
   CallRuntimeFromDeferred(Runtime::kStringCharCodeAt, 2, instr);
-  if (FLAG_debug_code) {
-    __ AbortIfNotSmi(v0);
-  }
+  __ AssertSmi(v0);
   __ SmiUntag(v0);
   __ StoreToSafepointRegisterSlot(v0, result);
 }