Environment

Windows build number: 10.0.19041.388
Windows Terminal version (if applicable): 1.1.2021.0

Steps to reproduce

• Open Windows Terminal
• setx WSLENV "${env:WSLENV}:TEST/p"
• Close and reopen Windows Terminal
• echo $env:WSLENV

Expected behavior

WT_SESSION:WT_PROFILE_ID:TEST/p

Actual behavior

WT_SESSION:WT_SESSION::WT_PROFILE_ID:TEST/p:WT_PROFILE_ID

I think the right thing to do here is to split WSLENV by : and check those vars are already set instead of just simply prepending and appending a string.

Probable related PRs:

• Add WT_SESSION to WSLENV so it propagates into WSL #4157
• Add WT_PROFILE_ID to the environment of the spawned process #4852