Revert OneByteString back to ISO Latin-1 instead of ASCII

runtime/vm/object_test.cc

Index: runtime/vm/object_test.cc
===================================================================
--- runtime/vm/object_test.cc	(revision 14982)
+++ runtime/vm/object_test.cc	(working copy)
@@ -576,13 +576,13 @@
 
   // Create a 1-byte string from an array of 2-byte elements.
   {
-    const uint16_t char16[] = { 0x00, 0x1F, 0x7F };
+    const uint16_t char16[] = { 0x00, 0x7F, 0xFF };
     const String& str8 = String::Handle(String::New(char16, 3));
     EXPECT(str8.IsOneByteString());
     EXPECT(!str8.IsTwoByteString());
     EXPECT_EQ(0x00, str8.CharAt(0));
-    EXPECT_EQ(0x1F, str8.CharAt(1));
-    EXPECT_EQ(0x7F, str8.CharAt(2));
+    EXPECT_EQ(0x7F, str8.CharAt(1));
+    EXPECT_EQ(0xFF, str8.CharAt(2));
   }
 
   // Create a 1-byte string from an array of 4-byte elements.