Bug fix and feature.
Description:
The setenv was done in runtest but it has the effect will linger
onto the next test. So, if the first test sets $CXX to a certain
value, it lingers on the all following tests of the same host.
This is usually not desired.
Solution:
Move the actual setenv code to snapshot. Runtest now just parses them
and pass along the setenv request to snapshot.
Platforms tested:
no h5comittest which does not really test the change.
Hand tested in eirene with Tg-NCSA.
Misc. update:
4e98e2d19a