Revision 669373

Part of fix for Jira issue XALANJ-2447.

The handling of exclude-result-prefixes for an xsl:stylesheet had the complete
set of excluded prefixes accumulated on the xsl:stylesheet for the main
stylesheet module.  However, the scope of the attribute is supposed to consist
only of elements that are direct descendants of an element that has the
attribute, and does not extend to imported or included stylesheets.  The same
is true of namespaces excluded because they have been declared as extension
element prefixes.

Fixed this by maintaining a stack of excluded prefixes that's pushed on entry
to the Stylesheet.parseOwnChildren method and popped on exit from the same.
The push operation clears the current set of excluded prefixes and the pop
operation restores the set of excluded prefixes that were in effect for the
importing or including stylesheet.

Reviewed by Christine Li (jycli () ca ! ibm ! com)