at the start of rtalloc1(). This backs out part of revs 1.83 and 1.85.
Profiling on an i386 showed that that for sending tiny packets using
bge, -current takes 7 bzero()s where RELENG_4 takes only 1, and that
bzero()ing is now the dominant overhead (10-12%, up from 1%, but
profiling overestimated this a bit). This commit backs out 2 of the
6 extra bzero()s (1 in each of 2 calls per packet to rtalloc1()). They
were the largest ones by byte count (48 bytes each) but perhaps not
by time (small misaligned ones might take longer).
6f5967c087