Remove an alias from Canonicalize

spec.html

@@ -37176,11 +37176,10 @@ <h1>
             1. Assert: _ch_ is a UTF-16 code unit.
             1. Let _cp_ be the code point whose numeric value is the numeric value of _ch_.
             1. Let _mapped_ be toUppercase(« _cp_ »), according to the Unicode Default Case Conversion algorithm.
-            1. Let _mappedStr_ be CodePointsToString(_mapped_).
-            1. If the length of _mappedStr_ ≠ 1, return _ch_.
-            1. Let _mappedCU_ be _mappedStr_'s single code unit element.
-            1. If the numeric value of _ch_ ≥ 128 and the numeric value of _mappedCU_ &lt; 128, return _ch_.
-            1. Return _mappedCU_.
+            1. If the length of _mapped_ ≠ 1 or the length of CodePointsToString(_mapped_) ≠ 1, return _ch_.
+            1. Let _mappedCP_ be the single code point element of _mapped_.
+            1. If the numeric value of _ch_ ≥ 128 and _mappedCP_ &lt; 128, return _ch_.
+            1. Return the code unit whose numeric value is _mappedCP_.
           </emu-alg>
           <emu-note>
             <p>In case-insignificant matches when HasEitherUnicodeFlag(_rer_) is *true*, all characters are implicitly case-folded using the simple mapping provided by the Unicode Standard immediately before they are compared. The simple mapping always maps to a single code point, so it does not map, for example, `ß` (U+00DF LATIN SMALL LETTER SHARP S) to `ss` or `SS`. It may however map code points outside the Basic Latin block to code points within it—for example, `ſ` (U+017F LATIN SMALL LETTER LONG S) case-folds to `s` (U+0073 LATIN SMALL LETTER S) and `K` (U+212A KELVIN SIGN) case-folds to `k` (U+006B LATIN SMALL LETTER K). Strings containing those code points are matched by regular expressions such as `/[a-z]/ui`.</p>