libc: Don't filter out sigsetjmp from libc-gen

Issue #1085
GNU Nano noux port, noux_nano.run
tool: test result output of amtterm reset

"amtterm reset" returns 0 as exitcode even if the reset command failed.
So check explicitly the output of the command to detect the error case.
libc_fs: Make plugin thread safe

Issue #1090
rump: Add panic message
vbox: Increase quota for rump_fs in auto test