test_different_benchmarks tests only 3 companies all in same sector

[MichaelTiemannOSC]

Issue #163 was caught by accident while reviewing results from test_different_benchmarks. The pint code was complaining about units being stripped, and I was looking to see whether we could do a better job at using PintArrays to keep units tidy. While all the data for the test case said yes, a test case that spanned across sectors using different intensity metrics clearly says no.

test_different_benchmarks should be enhanced to additionally test across different sectors (covered by the different benchmarks).

Perhaps we should also consider creating an XFAIL case where one benchmark has sector coverage and another does not.

This does not depend on the template-v2 branch. Issue #165 does depend on that branch, and will likely subsume this issue if this issue is not worked first.