Fix index register assignment in LoadFieldByIndex for arm, arm64, and mips.

src/arm64/lithium-arm64.cc

Index: src/arm64/lithium-arm64.cc
diff --git a/src/arm64/lithium-arm64.cc b/src/arm64/lithium-arm64.cc
index 2411b7074d15f2ca22dfd3956e393d9fd74d0f23..f5f6b8e2cd08acea33a316981547afa2e60ce9fe 100644
--- a/src/arm64/lithium-arm64.cc
+++ b/src/arm64/lithium-arm64.cc
@@ -2686,7 +2686,7 @@ LInstruction* LChunkBuilder::DoCheckMapValue(HCheckMapValue* instr) {
 
 LInstruction* LChunkBuilder::DoLoadFieldByIndex(HLoadFieldByIndex* instr) {
   LOperand* object = UseRegisterAtStart(instr->object());
-  LOperand* index = UseRegister(instr->index());
+  LOperand* index = UseRegisterAndClobber(instr->index());
   LLoadFieldByIndex* load = new(zone()) LLoadFieldByIndex(object, index);
   LInstruction* result = DefineSameAsFirst(load);
   return AssignPointerMap(result);