MFC r231858:

MFC r231858:

 Add regression tests scripts for multi-IP FIBs exercising the send,
 receive and forward path tagging packets with both the ifconfig fib
 option or using ipfw, running ICMP6, TCP/v6 and UDP/v6 tests and
 testing both setfib(2) as well as the SO_SETFIB socket option.

 At 16 FIBs a total of over 64k return codes/replies/stati are checked,
 sometimes multiple times (in different ways, e.g. the reflected request
 as well as ipfw counter values).

 The scripts need two or three machines to run and are thus not added
 to the tools/regression framework but only to tools/test.

MFC r232114:

 Update scripts to work around two sh(1) bugs found in stable/8:
 1) _x=$((_x + 1)) does not work while x=$((x + 1)) does.
 2) Parameter Expansion, esp. "${x%%bar}" does not work if quoted.

 Correct typos and improve some details forwarding.sh already
 had in initiator, esp. related to ipfw accepting if the default
 is deny.

 Add an extra stat call to the "delay" function in addition to the
 touch which together is still a lot faster than sleep 1 but seems
 to help a lot more to mitigate the unrelated kernel race seen.

Sponsored by:	Cisco Systems, Inc.

git-svn-id: svn://svn.freebsd.org/base/stable/8@232567 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f