[Validator] Fixed StaticMethodLoaderTest to actually test something

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

This test is not testing anything, except for whether PHP throws a strict standards error when invalid code is loaded.

I disabled error reporting for this test, so that the actual functionality (ignoring static+abstract functions) is tested.