Remove FLAG_opt_safe_uint32_operations.

src/x87/lithium-x87.cc

Index: src/x87/lithium-x87.cc
diff --git a/src/x87/lithium-x87.cc b/src/x87/lithium-x87.cc
index 3169a864538272ce5ebaa67db5dabd4fcdec1724..c23bce4e98bf298a1d1b7d1a33d62fc2a7e64f0d 100644
--- a/src/x87/lithium-x87.cc
+++ b/src/x87/lithium-x87.cc
@@ -736,11 +736,7 @@ LInstruction* LChunkBuilder::DoShift(Token::Value op,
     // Shift operations can only deoptimize if we do a logical shift by 0 and
     // the result cannot be truncated to int32.
     if (op == Token::SHR && constant_value == 0) {
-      if (FLAG_opt_safe_uint32_operations) {
-        does_deopt = !instr->CheckFlag(HInstruction::kUint32);
-      } else {
-        does_deopt = !instr->CheckUsesForFlag(HValue::kTruncatingToInt32);
-      }
+      does_deopt = !instr->CheckFlag(HInstruction::kUint32);
     }
 
     LInstruction* result =