server: report the isolate working directory from get_info (#26773)
* server: report the isolate working directory from get_info
Without an explicit cwd, get_info fell back to the server process
working directory even when a tools runtime was configured. That named a
host path no tool would ever run in, since an isolate starts in a
directory of its own.
It now asks the isolate for its working directory in that case, and
keeps the process one only when the tools run on the host.
* remove redundant comment
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Co-authored-by: Xuan-Son Nguyen <thichthat@gmail.com>