parser_test only needed the directory-names for
the tests to run. This replaces f.Readdir() with
f.Readdirnames() to only return the names.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
If previous line ends with whitespace, or next line starts with whitepsace
we need to preserve a space otherwise things line:
RUN echo\
hello
will appear as: RUN echohello
Noticed this while looking at #5744 because he had lines ending in &&\
Signed-off-by: Doug Davis <dug@us.ibm.com>
