Fixed access to memory out of range

Fixed the code accessing outside the range of the character string.
When running the test in Xcode, Guard Malloc (libgmalloc) detected it and caused a runtime error.

Author: tid-kijyun

CoreFoundation/String.subproj/CFStringEncodings.c

@@ -636,7 +636,7 @@ CFIndex __CFStringEncodeByteStream(CFStringRef string, CFIndex rangeLoc, CFIndex
                 }
 
                 CFIndex uninterestingTailLen = buffer ? (rangeLen - MIN(max, rangeLen)) : 0;
-                while (*ptr < 0x80 && rangeLen > uninterestingTailLen) {
+                while (rangeLen > uninterestingTailLen && *ptr < 0x80) {
                     ++ptr;
                     --rangeLen;
                 }