Removes invalid test for bad UTF-8 and replaces it with an octal test.

Fixes #1.

"I think I had grabbed the example from: http://www.fileformat.info/info/unicode/char/1d11e/index.htm
C/C++/Java source code "\uD834\uDD1E"

From http://en.wikipedia.org/wiki/UTF-8
"According to the UTF-8 definition (RFC 3629) the high and low surrogate halves used by UTF-16 (U+D800 through U+DFFF) are not legal Unicode values, and the UTF-8 encoding of them is an invalid byte sequence and thus should be treated as described above."

So I think the test case itself is incorrect and Go1.1 probably got more strict. So I'll remove the test and close this issue."

Adding an octal test because why the hell not.