RFR (XXS): JDK-8008944 correct typos

[Tim Bell]

Magnus:

> Bug: https://bugs.openjdk.java.net/browse/JDK-8008944
>
> Fix some typos in comments and messages, as pointed out by users.
>
> Webrev: http://cr.openjdk.java.net/~ihse/JDK-8008944-fix-typos/webrev.01

Looks good to me.

/Tim