[2.x] `reboot` causes sbt to exit

steps

1. Create a minimal build

   # project/build.properties
   sbt.version=2.0.0-RC12
   

   // build.sbt
   lazy val root = project.in(file("."))
   

2. Run sbt in the project dir
3. Run reboot

problem

reboot says it's booting the sbt server, then says the server closed:

sbt:root> reboot
[info] sbt server is booting up

sbt server connection closed.

expectation

reboot should reboot the server and drop you back into the sbt shell