Run tests for both the built-in and extracted WordCloud block.
The tests are mostly compatible with both versions of the block,
except for a few places where the XBlock framework and the
built-in XModule system differ which we've had to handle using
conditionals.
This moves us closer to enabling the extracted WordCloud block
by default and eventually removing the built-in block.
Part of: https://github.com/openedx/edx-platform/issues/34840
4a9fc77ecb