master: Obsolete dependency for Swiss maps

[stefanb]

Go 1.24 and 1.25 have Swiss maps enabled by default, with option to disable them via GOEXPERIMENT=noswissmap environment variable.
Upcoming Go 1.26 and later will have Swiss maps always enabled.

Since pebble (on master branch) already requires at least Go 1.25:

pebble/go.mod

Line 60 in 4bce934

go 1.25.3

...the dependancy on github.com/cockroachdb/swiss Go module for Swiss maps should no longer be needed.

This would lower the maintenance with every future Go release.

Jira issue: PEBBLE-1312

[RaduBerinde]

We use swiss map together with a custom cgo allocator to avoid GC having to go through the huge cache maps. I don't think we can use the built-in map.

[stefanb]

If this is the case, perhaps cgo allocator in cockroaches/swiss module could be moved outside of the go version build constraints?

[RaduBerinde]

Sorry, I don't quite understand what you propose - can you expand?