HPCC-10413 - Reinstate non-sequential subfile orders

A regression was introduced way back in 3.10.0, which
meant that the orders of subfiles were ignored, meaning
AddSuperFile @ position, was effectively being ignored.
Worse than that, it also meant the internal representation
of order of subfiles differed from the DFS meta file order,
which consequently cause bugs like HPCC-10287.

This commit:
1) Reinstates ordered subfiles as defined by SubFile @num
2) Rollsback the previous 4.2 commit which asserted the SubFile's
must have sequential order
3) Rollsback the daliadmin checksuperfile addition for OOO
SubFile's
4) Removes spurious "subfile:" tracing added in HPCC-9218

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #5148 from jakesmith/hpcc-10413

HPCC-10413 - Reinstate non-sequential subfile orders

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>
HPCC-10423 Fix regression xpath('') shouldn't output xml tag

xpath('') is used to store mixed content when a tag with both attributes
and content are needed.

<tag att='mixed'>content</tag>

This regression caused the content to be inside an extra tag.

<tag att='mixed'><name>content</name></tag>

Signed-off-by: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Merge branch 'empty_xpath_out' into candidate-4.2.0

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Community Edition 4.2.0-2 Gold

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>