Expore ignore tests directory

[jack-worman]

Tests are useless outside the actual project.
It also gets in the way of IDE's because it suggests global test functions like function variable($var) {} from GetMethodParametersTest

[jrfnl]

This has been discussed multiple times and this change has already been made for the 4.x branch, but will not be accepted for the 3.x branch.

See #548, #1908, #3158, #3176, #3204 (amongst others)

[jack-worman]

Thanks for the response and sorry for the noise.