Separate suite test parallelism from build parallelism
Separate suite test parallelism from build parallelism

Separates the test suite's test execution parallelism from build
parallelism, and reduces the former to not exceed the processor count
(which typically does not help performance and may hinder it, unlike for
build parallelism).

Review-URL: https://codereview.appspot.com/264710043

AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio,AmesianX/dynamorio