Minor touch-ups in start_test.
Minor touch-ups in start_test.

[reviewed by Elliot]

I wanted to make it more readable esp. w.r.t. GRAPHFILES notation,
and also prepare it for my upcoming change for an alternative GRAPHFILES.

* In the "CHPL_TEST_PERF_DIR must be set" warning, print the actual
default being used.

* Drop the trailing / in $compperfdir, for simplicity.

* Updated the message upon running checkGraphfiles.

* Renamed $graphFile to $compGraphList, for ease of grepping.

* Replaced $CHPL_HOME/test/GRAPHFILES with $execGraphList.
I intend to let the user control this with an option.


git-svn-id: 88467cb1fb04b8a755be7e1ee1026be4190196ef@22773 3a8e244f-b0f2-452b-bcba-4c88e055c3ca

hildeth/chapel,sungeunchoi/chapel,sungeunchoi/chapel,hildeth/chapel,CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,chizarlicious/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,hildeth/chapel,CoryMcCartan/chapel,hildeth/chapel,chizarlicious/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,sungeunchoi/chapel,chizarlicious/chapel,sungeunchoi/chapel,chizarlicious/chapel,sungeunchoi/chapel,CoryMcCartan/chapel,sungeunchoi/chapel,chizarlicious/chapel,hildeth/chapel,chizarlicious/chapel,hildeth/chapel