Add tests for FuncNameInferrer.

There were no explicit tests for FuncNameInferrer (though, some tests might
implicitly rely on it working properly in the common cases). Afaics, there were
no tests which would exercise inferring two byte function names or escaped
function names.

R=rossberg@chromium.org
BUG=

Review URL: https://codereview.chromium.org/310063002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@21649 ce2b1a6d-e550-0410-aec6-3dcde31c8c00