enhance pass-by-ref plugin to detect large arguments

Detect arguments larger than 64 chars passed by value.

Change-Id: I9b0ea9ccb99d115984a26eab67c9cf6afd5f6cae
Signed-off-by: Stephan Bergmann <sbergman@redhat.com>
fdo#78949 Handle (SAXParse-)Exception that can't pass getAllRelationships

...like it was already done in the similar else branch of
ReadRelInfoIfNecessary.  The call site at GetAllRelationshipsIfAny will
translate an m_nRelInfoStatus that remained RELINFO_NOT_INIT into an
IOException.

Change-Id: I79c601acd23b3b0020c7b4de4c20b0282524bce1