v8 2.1 branch: Fix minor error in optimized comparison to single-character string.

src/ia32/codegen-ia32.cc

Index: src/ia32/codegen-ia32.cc
===================================================================
--- src/ia32/codegen-ia32.cc	(revision 4398)
+++ src/ia32/codegen-ia32.cc	(working copy)
@@ -2428,7 +2428,8 @@
     left_side_constant_null = left_side.handle()->IsNull();
     left_side_constant_1_char_string =
         (left_side.handle()->IsString() &&
-         (String::cast(*left_side.handle())->length() == 1));
+         String::cast(*left_side.handle())->length() == 1 &&
+         String::cast(*left_side.handle())->IsAsciiRepresentation());
   }
   bool right_side_constant_smi = false;
   bool right_side_constant_null = false;
@@ -2438,7 +2439,8 @@
     right_side_constant_null = right_side.handle()->IsNull();
     right_side_constant_1_char_string =
         (right_side.handle()->IsString() &&
-         (String::cast(*right_side.handle())->length() == 1));
+         String::cast(*right_side.handle())->length() == 1 &&
+         String::cast(*right_side.handle())->IsAsciiRepresentation());
   }
 
   if (left_side_constant_smi || right_side_constant_smi) {