The install prefix was determined incorrectly for static relocatable
builds. The reason was that for those builds, QLibraryInfo::path()
returns the application directory, which is <prefix>/bin for qmake and
qtpaths.
Fix this by removing the bin directory part from the installation prefix
that QLibraryInfo returns if qmake/qtpaths are used.
Fixes: QTBUG-102877
Change-Id: I2e9ff96ded0ee2a7802b265741a3cfbe2bf0a4ba
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>