Replace "fast" and "slow" with fpu and int in loader.c.  Also add a comment explaining ISA lists.  r=wtc. bug 303508.
Replace "fast" and "slow" with fpu and int in loader.c.  Also add a
comment explaining ISA lists.  r=wtc. bug 303508.

thespooler/nss,thespooler/nss,thespooler/nss,thespooler/nss,thespooler/nss,thespooler/nss,thespooler/nss