Let's make this non-inline...

Change-Id: Ib427cea392c953e6bce121bfe82e9215eb1bb99a
fdo#77990: Intern strings for hybrid strings during import.

Change-Id: I269497cac645e486ac08bb2b011df1b5b23dc021
fdo#77990: Write test for this, using the 2nd test document submitted.

Change-Id: I70d71bb21ff43aeb49339ff1f1d9e73c923e0201