Previously, the early error prohibiting duplicate entries in
UniqueFormalParameters was only tested in terms of async functions. In
one case, this was misattributed to UniqeFormalParameters and only
enforced for strict mode code.

Extend coverage to the other function-creating productions which include
UniqueFormalParameters (i.e. method definitions and non-async arrow
functions), and update the existing tests to more accurately describe
the source of the error.

Closes #1634.

Early errors may result from parsing the source text of a test file, but
they may also result from parsing some other source text as referenced
through the ES2015 module syntax. The latter form of early error is not
necessarily detectable by ECMAScript parsers, however. Because of this,
the label "early" is not sufficiently precise for all Test262 consumers
to correctly interpret all tests.

Update the "phase" name of "early" to "parse" for all those negative
tests that describe errors resulting from parsing of the file's source
text directly. A forthcoming commit will update the remaining tests to
use a "phase" name that is more specific to module resolution.

This pattern makes expectations more explicit by making test files more
literal.

Authored via the following command:

   $ find test -type f -print0 | \
       xargs -0 sed \
         -i 's/^\(\s*\)negative:\s*SyntaxError\s*$/\1negative:\n\1  phase: early\n\1  type: SyntaxError/g'

Closes #479