Performance regression in TDML processor

While working on a customer project we noticed a significant increase in the amount of time it took to run our test suit (over 600 tests) after upgrading from Daffodil 2.7.0 to 3.2.1. We were seeing roughly a 4x increase in time to complete the same set of tests.

I've narrowed the performance regression to commit 0700ee8dc9531497f3e8b0fdf9266f8e3b105c27 which involved a removal of the schema compilation cache, which is likely causing the schema to need to be recompile much more frequently.

We use a relatively large schema (over 10,000 lines), but it is the same schema used for all tests.