Use system command instead of Bash builtin without specifying the full path

Assuming env is in your path:

env kill -p http

env runs the executable file named by its first argument in a (possibly) modified environment; as such, it does not know about or work with shell built-in commands.

This produces some shell job control cruft, but doesn't rely on an external command:

exec kill -p bash &

exec requires an executable to replace the current shell, so doesn't use any built-ins. The job is run in the background so that you replace the forked background shell, not your current shell.