Tests in jscore should not use jsTest.name() for its collection name

The tests projection_dotted_paths.js and explain_agg_write_concern.js both do something like

let coll = db.getSiblingDB("blah").getCollection(jsTest.name());

coll.drop()

This is unfortunate because, in the parallel suite, the name of the test is "basicPlus", which means that the two tests will conflict with each other and drop each other's data.