low: xmlutil: Handle XML comments properly in xml_cmp
low: xmlutil: in xml_cmp, s/print/common_debug/
test: Update regression test common excludes
Exclude commands including temporary file names
and commands that are called in most tests.
test: Update expected output from regression tests
After making sure all external calls actually get
logged when given -R, the test cases need to be updated
with those previously invisible calls.