redundant_pattern_matching: Option and Result methods stabilized as const

[CDirkx]

With rust#76135 and rust#76136 the methods is_some, is_none, is_ok and is_err will be stabilized as const. This makes them valid replacement suggestions again for Clippy within a const context, which was disabled in #5724.

The tests redundant_pattern_matching and redundant_pattern_matching_const_result thus need to be updated. I'm opening up this issue to reference in those modified tests.

Theses changes will be applied to the rustc in-tree version, as it currently blocks the stabilization of these methods.

[RalfJung]

In-tree changes to clippy are synced back periodically, so I am not sure this issue is even necessary (but maybe I am out of date wrt. clippy processes).

[flip1995]

Thanks for the heads up! Issues like this are not really necessary, since our CI currently already screams at us, if we haven't synced a Clippy change from rustc.

On bigger Clippy changes it is always nice to get pinged (@rust-lang/clippy), though.

cc #6071