Android: Fix a bug that unselecting the first <option> in <select multiple> selecting the first <option> again.

<select multiple> has menulist appearance on Android. Though menulist always
select an option, <select multiple> should have API compatibility with
non-Android.

BUG=325038
TEST=automated

Review URL: https://codereview.chromium.org/102663004

git-svn-id: svn://svn.chromium.org/blink/trunk@163513 bbb929c8-8fbe-4397-9dbb-9b2b20218538