Do not store code snippets in BindingRuntimeContext
Analysis of a heap dump shows we retain a fair amount of strings which
represent the QNAME member of generated classes via ConstantImpl. This
should not be happening, as the logic to create QNames in generated
classes should be part of the templates and only emitted to source code.
Teach ClassTemplate how to generate QName constants and only store the
QName in the Constant, saving the overhead of Strings.
Change-Id: I41951f969e273bc2ef4527ef3d95d4bed45c1b7f
Signed-off-by: Robert Varga <rovarga@cisco.com>