[turbofan] Relax index type constraints for StringCharAt/StringCharCodeAt.

src/compiler/types.h

Index: src/compiler/types.h
diff --git a/src/compiler/types.h b/src/compiler/types.h
index a4c54c391eec4b7757ae855cddc2823cac36f07f..0b50bf46aa27e51c4005c8c751b85df693994b8b 100644
--- a/src/compiler/types.h
+++ b/src/compiler/types.h
@@ -139,6 +139,7 @@ namespace compiler {
   V(Unsigned32OrMinusZero,      kUnsigned32 | kMinusZero) \
   V(Unsigned32OrMinusZeroOrNaN, kUnsigned32 | kMinusZero | kNaN) \
   V(Integral32,                 kSigned32 | kUnsigned32) \
+  V(Integral32OrMinusZeroOrNaN, kIntegral32 | kMinusZero | kNaN) \
   V(PlainNumber,                kIntegral32 | kOtherNumber) \
   V(OrderedNumber,              kPlainNumber | kMinusZero) \
   V(MinusZeroOrNaN,             kMinusZero | kNaN) \