Remove fragile equal-pointers-unequal/*/print3.rs tests.
These tests were added in #127003
The print3.rs tests stop working when I change implementation details of format_args!(). (For example, in https://github.com/rust-lang/rust/pull/139175 and https://github.com/rust-lang/rust/pull/139135). These tests shouldn't rely on such implementation details. It gets in the way for format_args!() improvements.
If they test anything that aren't already covered by the other tests in this directory, they should be expressed in a less fragile way that doesn't rely on internal details of format_args!().
cc ``@GrigorenkoPV,`` author of these tests.
5b46e2462a