[PATCH] BZ# 18125: setcontext: Call exit, not _exit, after last linked context executes.

[Pedro Alves]

OOC, and for my own education, why bother with writing a file in
the exit handler, and then checking that in the script on success
exit, instead of just printf("PASS: ...") directly in the test
program's exit handler?

(I wondered that because I noticed that the exit handler
will run in many of the FAIL cases too, though I realize
that those exit with exit code != 0 and thus won't return
in PASS from the script).

Thanks,
Pedro Alves