HPCC-9417 Fix XPATH being ignored for nested records

This was a regression in 3.10.8.  XPATHs were no longer being used
for FVFFbeginrecord and FVFFendrecord column types resulting in a
mismatch between output and xml schema that can cause the EclWatch
result viewer xslt to not output records whose field names had
been modified via xpath.

Signed-off-by: Anthony Fishbeck <Anthony.Fishbeck@lexisnexis.com>