The biggest issue here is that Configurable objects needed to be
cloned before appended to one another, otherwise some Configurables
that were used in defaults could be edited after being applied to one
module and apply a different value to another module.
Also fix an issue where a select without a defined appendWrapper
always evaluated to nil.
I plan to make a followup refactor cl to make these things clearer,
but start with the bugfix.
Bug: 323382414
Test: m nothing --no-skip-soong-tests (see other cl in topic for tests)
Change-Id: Icf68d0ee1779c76bfb3d68db43b35d7e09bc0dd9
70b814a964