Canonical encoding name : windows-949 => EUC-KR
This is the chromium side of a blink change at
https://codereview.chromium.org/25870005
Until the corresponding blink is re-landed (it's landed but reverted),
disable EUC-KR-related test temporarily.
BUG=
277027,
95963
TEST=browser test: BrowserEncodingTest.* and EncodingAlias*.