Reshuffle the generation of the OKURO-NASI entries to speed up build

Reshuffle the generation of the OKURO-NASI entries to speed up build

* leim/Makefile.in (all): Remove the ja-dic target from all -- we
don't need this file generated before we generate the .elc files.
(generate-ja-dic): Add new target.

* lisp/Makefile.in (.PHONY, generate-ja-dic): Add new target.
(all): Make all depend on the new generate-ja-dic target so that
the OKURO-NASI entries are computed while the .elc files are
compiled.  On a AMD Ryzen 9 5950X 16-Core Processor this brings
compilation time on a "make -j32 bootstrap" down from 1m52s to 1m34s.