Rollup merge of #139176 - m-ou-se:print3, r=compiler-errors

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 #139175 and #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.

Author: matthiaskrgr