Rollup merge of rust-lang#118314 - WaffleLapkin:rename_collectionstests, r=cuviper

Rename `{collections=>alloc}{tests,benches}`

The crate is named `alloc` so this makes more sense. Ig this is fallout from rust-lang#42648?

Author: matthiaskrgr

library/alloc/Cargo.toml

@@ -17,11 +17,11 @@ rand = { version = "0.8.5", default-features = false, features = ["alloc"] }
 rand_xorshift = "0.3.0"
 
 [[test]]
-name = "collectionstests"
+name = "alloctests"
 path = "tests/lib.rs"
 
 [[bench]]
-name = "collectionsbenches"
+name = "allocbenches"
 path = "benches/lib.rs"
 test = true