The changes in this ticket would change the log lines slightly for disagg JS tests to output a different process prefix from the usual "sh<PID>" format. This may affect DevProd log parsing tools such as https://github.com/10gen/build-baron-tools/blob/2ecbae1f8aaa0496c2d1a7fedc5f745789164a47/src/bb/logpipeline/logmux/testlogmux.py.

Description of Linked Ticket

The mongo legacy shell, used primarily for testing, supports spawning processes where the process output will be interleaved with the JS test script it is current running. The output of the spawned process is prefixed by the process ID. In JS tests where a small number of external programs are launched for short time, this logging convention is sufficient. For JS tests that may spawn multiple processes that run for the duration of the test, this log prefixing scheme could be improved by allowing the test to provide an additional prefix with a more meaningful context-specific name.