Correct typo of zn_CN to zh_CN

zn is not an assigned ISO 639 language code and likely to be a typo
of zh here. Correct it to the correct value zh to avoid code copy
the wrong value for other tests.

Bug: 1072175
Change-Id: I9141966d4ab9468b86a2142ad55bfbde2c57f3f5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2157926Reviewed-by: Jungshik Shin <jshin@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#762549}

ui/base/l10n/l10n_util_unittest.cc

@@ -546,7 +546,7 @@ TEST_F(L10nUtilTest, IsValidLocaleSyntax) {
   EXPECT_TRUE(l10n_util::IsValidLocaleSyntax("en_IE_u_cu_IEP"));
   EXPECT_TRUE(l10n_util::IsValidLocaleSyntax("en_IE@currency=IEP"));
   EXPECT_TRUE(l10n_util::IsValidLocaleSyntax("fr@x=y"));
-  EXPECT_TRUE(l10n_util::IsValidLocaleSyntax("zn_CN@foo=bar"));
+  EXPECT_TRUE(l10n_util::IsValidLocaleSyntax("zh_CN@foo=bar"));
   EXPECT_TRUE(l10n_util::IsValidLocaleSyntax(
       "fr@collation=phonebook;calendar=islamic-civil"));
   EXPECT_TRUE(l10n_util::IsValidLocaleSyntax(