XSLT 1.0 names every QName-keyed declaration by expanded name, so two prefixes
bound to the same namespace name the same thing. mode and variable names were
already resolved this way; named templates, xsl:key, xsl:attribute-set, and
xsl:decimal-format names were still keyed and compared as raw prefix strings.
A declaration name now resolves to {uri}local at parse time, and the references
resolve their prefix against the in-scope namespaces the same way: call-template
and use-attribute-sets at parse time, and the key() name argument and
format-number's format name at evaluation (a shared Library.expandedName helper
covers the two runtime sites). The parse-time expansion reuses a factored
expandedQName helper shared with mode and variable.
Closes Apache Xalan conformance cases namedtemplate16, attribset48, idkey53.
Full suite 1632 tests green in debug and release; the Xalan suite passes.