Fix art script and golem builds with conscrypt.

1) When no bootclasspath is given to the art script, also add conscrypt to
the list.
2) Have build-art-target-golem deapex the prebuilt conscrypt apex.

Bug: 154074847
Test: build-art-target-golem
Change-Id: I648c23e05ad7d8f3387293c287fee3ba8380f1fb
2 files changed