Summary

Allow traceExceptions to be set at startup (config / --setParameter) so that developers can enable full exception stack tracing directly from the resmoke command line.

Motivation

• Today traceExceptions is effectively runtime-only (via setParameter), so early exceptions (including during startup) are not traced.
• For debugging BFs, it’s convenient to flip a single resmoke option that forwards --setParameter traceExceptions=true to all fixtures.
• This is a dev-only knob; default remains false and production users don’t need to change anything.

Proposal

• Make traceExceptions behave like a normal startup+runtime server parameter:
  • Accept it in the config file under setParameter.
  • Accept it via --setParameter traceExceptions=true on mongod/mongos.
• Ensure the startup value takes effect early enough that startup-time exceptions are traced.

Notes

• This makes it trivial to add a resmoke option like --mongodSetParameters='{traceExceptions: true}' for ad-hoc debugging runs.