Ensure executable .skipifs have the full environment.
Ensure executable .skipifs have the full environment.

Update sub_test to parse output of `printchplenv --simple` and pass it to the
skipif file when invoking the executable form.

Previously, this form of .skipif did not have access to the full environment
(e.g. anything not set by user in environment).

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