Automatic handling of incompatible hxb cache

[tobil4sk]

For haxelib run scripts running via eval, it is useful to be able to create a hxb cache to reduce script startup times: HaxeFoundation/haxelib#674

It would be nice if haxe could provide automated handling of the hxb cache to make sure it's up to date. Haxelib would just provide haxe with a hxb file path, and then haxe would automatically:

• Use the hxb file if it exists and is compatible with the current haxe version
• If it is incompatible or corrupt, ignore it, compile from scratch, and generate a new hxb file

This would reduce the amount of interactions haxelib has to have with haxe to use the cache. This way, haxelib would just have to run a single haxe command.

@kLabz suggested something like:

haxe ... --hxb bin/main.hxb --hxb-lib bin/main.hxb -D hxb.skipVersionMismatch