Fix printchplenv to indicate more user-set env vars
Fix printchplenv to indicate more user-set env vars

printchplenv wouldn't display a star next to any indented variables
(CHPL_COMM_SUBSTRATE, CHPL_GASNET_SEGMENT, CHPL_NETWORK_ATOMICS). This
change makes it so we will indicate if these are set by a user.

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