jsontests.cpp uses inheritance to parse each string that it wants to test.

This is really wasteful and makes it difficult to see the differences among the tests in a group. The tests don't share common code. The file is about 3000 lines, and doesn't need to be.

I'd like to see us make some progress toward phasing out this kind of boilerplate-dominated testing.

The test for SERVER-8544 was too hard to add.