std: general purpose allocator: use AutoHashMap
std: general purpose allocator: use AutoHashMap

As pointed out by Sahnvour, AutoHashMap is both more convenient and will
have better performance in this case.

raulgrell/zig,raulgrell/zig,raulgrell/zig,raulgrell/zig,zig-lang/zig,zig-lang/zig,andrewrk/zig,andrewrk/zig,zig-lang/zig,raulgrell/zig