fix: unexpected spaces at token head

[blindFS]

This PR:

1. reduces case count Tracking issue: performance optimization #185 : 3376 -> 3146, WASM comp time: 3m40 -> 2m20
2. accidentally fixes the space issue of Assignment rhs includes all the white space after the assignment operator. #198 / hide-env / flags

[fdncred]

interesting. thanks! that's a pretty significant reduction.