Function canonical_symbol_name 

fn canonical_symbol_name(s: &str) -> SymbolName

Squeze spaces from a string to make a canonical symex name.

The caller must ensure that the passed-in string is indeed a single symex name. Meaning that the input "TYPE A" is valid but "A TYPE" and "ADD Y" are not, since neither the AE register name "A"nor the opcode "ADD" can be the first syllavble of a symex name containing a space.