Kill TraceBuilder::m_refCountedMemValue

We don't completely trust it and it wasn't providing a measurable perf
win.

Reviewed By: @bertmaher

Differential Revision: D992711
Make OSS Test Script a real test runner - at least human runnable

A bit of a redesign and better user-experience.

This script runs one or more open source (oss) framework unit tests via PHPUnit. Run one or multiple tests by explicitly naming them at thecommand line, or specify --all to run all available tests. You will see various forms of output. The first time running a test suite for a framework, gray dots will appear to set the baseline for future runs. On subsequent runs, you will see green dots for tests that have the same status as the previous run. If something changes, you will see a red F if a test went from pass to something else. You will see a green F if a test went from something else to pass. You will see a blue F if a test stayed in the failing range, but went from something like E to I or F to S.

The summary for a test show the overall pass percentage of the unit test suite, irrespective of previous runs. The output and diff files for a test suite will show what tests pass or fail, and have why they failed.

Example output: P2777440

Future: Add number of total tests to be run at beginning in a clean way; fbmakify the runner

Reviewed By: @ptarjan

Differential Revision: D991614
fix VIXL compilation on non-Linux

s/isnan/std::isnan/g

Reviewed By: @sgolemon

Differential Revision: D996133