CLDR-15368 Switch WHAT_GETROW to modern api, preliminary clean-up

[btangmu]

-Correction for new api xpath in cldrTable.getSingleRowUrl (theRow.xpathId not tr.rowHash)

-Move getPageUrl to cldrTable; make TABLE_USES_NEW_API private

-In cldrTable.js, always use sortMode = displaySets.default = ph

-Purge var from cldrTable.js, use const or let instead

-Remove old unused ALWAYS_REMOVE_ALL_CHILD_NODES and NEVER_REUSE_TABLE

-Make CLDR_VOTE_DEBUG false in cldrVote.js, suppress unneeded debug messages

-Simplify SortMode.java, PathHeaderSort.java, and DataSection.getRow

-Remove unused RefreshRow.jsp, CalendarSortMode.java, CodeSortMode.java, MetazoneSortMode.java, NameSort.java

-Make SurveyAjax.getRow private

-Fix some compiler warnings, especially in DataSection.java and SurveyAjax.java

-Remove dead code

-Comments

CLDR-15368

• [ ] This PR completes the ticket.