Tweak builtin symbol order for speed

* lib-src/make-docfile.c (compare_globals):
Make symbols 1 through 4 be t, unbound, error, lambda.
This is in addition to symbol 0 being nil.
This change improved ‘make compile-always’ performance by 0.6%
on my platform.
1 job for master in 50 minutes and 42 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Test
passed #2505
test-all

00:50:42