Add chpl_error() and chpl_internal_error(), indicating they halt execution.
Add chpl_error() and chpl_internal_error(), indicating they halt execution.

These will help Coverity Scan's analysis of NULL pointer dereferences.
Currently it is saying that we might dereference a NULL pointer because
it doesn't realize that a NULL test that does chpl_error() if true will
result in a halt.  It thinks execution will proceed through that.

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