Log Message:
Update py-angr to 8.20.7.27, along with associated packages.

Version is consolidated into devel/py-angr/version.mk now so the next
person to come along will know what else needs to be updated.

devel/py-pyvex distfiles are still kinda kludgey, and devel/py-angr's
tests don't run without binary samples that I got bored trying to
incorporate.