environment variable to disable JIT
Created originally on Bitbucket by Bernat Gabor
PyPy can be a lot slower for short-lived interpreter runs than CPython. In such cases disabling the JIT might help a bit. This is now possible via --jit off, however, this does not scale well if you don’t know if your target python is either CPython or PyPy. Adding an environment flag to turn off the JIT might allow one to work around this issue.
PS. Initially proposed in a discussion with @Ronan Lamy