Revert "islamicc should be canonicalized to islamic-civil (#747)" (#774)

This reverts commit da4f4385.

test/intl402/Intl/getCanonicalLocales/main.js

@@ -29,4 +29,6 @@ assertArray(gCL({'a': 0}), []);
 
 assertArray(gCL({}), []);
 
+assertArray(gCL(['ar-ma-u-ca-islamicc']), ['ar-MA-u-ca-islamicc']);
+
 assertArray(gCL(['th-th-u-nu-thai']), ['th-TH-u-nu-thai']);

test/intl402/Intl/getCanonicalLocales/preferred-subtag.js

-// Copyright 2016 Mozilla Corporation. All rights reserved.
-// This code is governed by the license found in the LICENSE file.
-
-/*---
-esid: sec-canonicalizelanguagetag
-description: Test for the replacement of a deprecated subtag with its preferred subtag.
-info: |
-  6.2.3 CanonicalizeLanguageTag ( locale )
-   It takes the steps specified in RFC 5646 section 4.5, or successor, to bring the language
-   tag into canonical form, and to regularize the case of the subtags.
-   RFC 5646 section 4.5 - 3rd point: Subtags are replaced by their
-   'Preferred-Value', if there is one.
-includes: [compareArray.js]
----*/
-
-var gCL = Intl.getCanonicalLocales;
-
-function assertArray(l, r) {
-  assert(compareArray(l, r), r);
-}
-
-// islamicc is deprecated and its preferred name is 'islamic-civil'.
-// See http://www.unicode.org/repos/cldr/tags/latest/common/bcp47/calendar.xml .
-assertArray(gCL(['ar-ma-u-ca-islamicc']), ['ar-MA-u-ca-islamic-civil']);