test: exclude new fs watch test for AIX

Pull Request check-list

Please make sure to review and check all of these items:

• [X ] Does make -j8 test (UNIX) or vcbuild test nosign (Windows) pass with this change (including linting)?
• [ X] Is the commit message formatted according to [CONTRIBUTING.md][0]?
• If this change fixes a bug (or a performance problem), is a regression test (or a benchmark) included?
• Is a documentation update included (if this change modifies existing APIs, or introduces new ones)?

NOTE: these things are not required to open a PR and can be done afterwards / while the PR is open.

Affected core subsystem(s)

fs

Description of change

As per https://github.com/nodejs/node/issues/5085 exclude new test from AIX until we have fixes for libuv for fs watching on AIX. Excluding test so AIX tests are green and we don't miss other regressions