FEX Unit tests

FEX has its own test suite for x86-64 emulation, and we also use gcc's target tests, posixtest, and gvisor's tests. We use a combination of CMake/CTest and python runner scripts.

We also regularly run and pass qemu's and valgrind's tests for validation, but those aren't in CI right now.

x86/64 testing

• A lot of handwritten assembly unit tests in 32Bit_ASM and ASM folders, run via our TestHarnessHelper
• A few handwritten IR tests in IR, run via our IRLoader
• gcc-target-tests-32 and gcc-target-tests-64, run via FEX. The tests binaries are in External/fex-gcc-target-tests-bins

Syscall testing

• 64-bit posixtest from http://posixtest.sourceforge.net/, run via FEX. The tests binaries are in External/fex-posixtest-bins
• 64-bit gvisor tests from https://github.com/google/gvisor, run via FEX. The tests binaries are in External/fex-gvisor-tests-bins