Instead of creating and destroying a SILProfiler
per TopLevelCodeDecl, setup a single profiler
for the top-level entry point function, and visit
all the TopLevelCodeDecls when mapping regions.
* Group tests for profiling instrumentation together, NFC
This will make it easier to test changes to the code coverage logic.
There are a handful of tests which relate to profiling which I have not
moved. These include tests for the driver and for the SIL optimizer. It
makes more sense to keep those tests where they are.
* Rename a test file, NFC
This file tests code coverage of primary files, so I've changed the name
of the file to reflect that.
* Simplify the check lines in a test, NFC
This file tests code coverage of closures. It had several check lines
which obscured the meaning of the test, and its check lines were in a
strange order.
Remove the extra checks and disable -emit-sorted-sil.
