Remove FLAG_opt_safe_uint32_operations.

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 83cf52b550cdf028f02f578c2bc8e2243e87a1ea..241bc4b20bfe705aaaa06580c473e367df521fae 100644
--- a/src/arm64/lithium-arm64.cc
+++ b/src/arm64/lithium-arm64.cc
@@ -2236,11 +2236,7 @@ LInstruction* LChunkBuilder::DoShift(Token::Value op,
                            (JSShiftAmountFromHConstant(instr->right()) == 0);
   bool can_deopt = false;
   if ((op == Token::SHR) && right_can_be_zero) {
-    if (FLAG_opt_safe_uint32_operations) {
-      can_deopt = !instr->CheckFlag(HInstruction::kUint32);
-    } else {
-      can_deopt = !instr->CheckUsesForFlag(HValue::kTruncatingToInt32);
-    }
+    can_deopt = !instr->CheckFlag(HInstruction::kUint32);
   }
 
   LInstruction* result;