Blacklist/unblacklist tests in secondary_reads_passthrough suite

Blacklisting: benchRun() cannot be overridden to be causally consistent, and will cause intermittent test failures not being able to read its own writes. It should not be tested in the secondary_reads_passthrough suite.

Unblacklisting: Tests that use eval() should be unblacklisted because eval() always goes to the primary. Also, we don't need to override the read/write concerns since the server read/write concern defaults are already the values we want.