Add a list of symbols for stable standard library crates
There are a few locations where the crate name is checked against an enumerated list of `std`, `core`, `alloc`, and `proc_macro`, or some subset thereof. In most cases when we are looking for any "standard library" crate, all four crates should be treated the same. Change this so the crates are listed in one place, and that list is used wherever a list of `std` crates is needed.
`test` could be considered relevant in some of these cases, but generally treating it separate from the others seems preferable while it is unstable.
There are also a few places that Clippy will be able to use this.
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