Use "javac -h" instead of "javah" to generate header files

This requires adding @Native annotations to CodeOption.Flag
members and updating the mapping to human-usable names in
src-disl-agent/dislagent.c and src-shvm-agent/disl/disl.h

Also ensure that the headers in src-disl-agent/codeflags.h and
src-shvm-agent/disl/codeflags.h are up-to-date with respect to
the file.
5 jobs for pre-java9-cleanup in 5 minutes (queued for 3 seconds)
Name Stage Failure
test compound Test
[services.d] starting services
[services.d] done.
[cmd] sh exited 0
[cont-finish.d] executing container finish scripts...
[cont-finish.d] done.
[s6-finish] syncing disks.
[s6-finish] sending all processes the TERM signal.
[s6-finish] sending all processes the KILL signal and exiting.
ERROR: Job failed: exit code 1