[crankshaft] Fix deopt loop in String.fromCharCode on non-int32 inputs.

src/crankshaft/hydrogen.cc

Index: src/crankshaft/hydrogen.cc
diff --git a/src/crankshaft/hydrogen.cc b/src/crankshaft/hydrogen.cc
index 33b0c27565d22ca57c4f05f32fa3c53858848e63..fda129fe9e6c5aa13e700ee1273ed5a927678152 100644
--- a/src/crankshaft/hydrogen.cc
+++ b/src/crankshaft/hydrogen.cc
@@ -8791,6 +8791,9 @@ bool HOptimizedGraphBuilder::TryInlineBuiltinMethodCall(
       if (argument_count == 2) {
         HValue* argument = Pop();
         Drop(2);  // Receiver and function.
+        argument = AddUncasted<HForceRepresentation>(
+            argument, Representation::Integer32());
+        argument->SetFlag(HValue::kTruncatingToInt32);
         HInstruction* result = NewUncasted<HStringCharFromCode>(argument);
         ast_context()->ReturnInstruction(result, expr->id());
         return true;