Like the symbols and the VM functions this is data that is static from startup until shutdown and has no need to be subjected to garbage collection. All things combined this reduces the amount of GC-sensitive objects at startup from 9600 to 600.
Symbols are very easy to manage once they are in a symbol table and there's lots of them so this reduces the amount of work the GC needs to do quite considerably.
After cleaning out compile-time-only symbols there will still be more than 2000 left, one for each function and one for each member variable of a class or struct.
This means more than 2000 object that won't need to tracked constantly by the garbage collector.
Note that loose fields which do occur during code generation will be GC'd just as before.
