Behavior of `split` peg special with `""` as first argument

[sogaiu]

As discussed here, the following invocation:

(peg/match ~(split "" (capture (to -1)))
           "hello there friends")

can lead to:

• OOM (of janet process) on Linux
• Crash (of janet process) on macos
• Machine unresponsive (screen went black and rebooted after waiting a while) on Windows 10

In contrast, the following two invocations do not:

(peg/match ~(any (capture ""))
           "hello there friends")
# =>
@[]

(peg/match ~(some (capture ""))
           "hello there friends")
# =>
nil