This script is rewrite of run-tests-exp.sh, and tries to achieve self-hosted
testsuite running in environments where neither CPython nor unix shell is
available. As run-tests-exp.sh, it requires complete set of .exp files
pre-generated with ./run-test --write-exp.

It seems the Mac will happily wipe out at least some of the data on
a freshly reset filesytem, if the filesystem was reset while plugged
into the Mac.

system() is the basic function to support automation of tasks, so have it
available builtin, for example, for bootstrapping rest of micropython
environment.

This renders it in yellow/orange box on RTD server.

This optimisation reduces the VM exception stack element (mp_exc_stack_t)
by 1 word, by using bit 1 of a pointer to store whether the opcode was a
FINALLY or WITH opcode.  This optimisation was pending, waiting for
maturity of the exception handling code, which has now proven itself.

Saves 1 machine word RAM for each exception (4->3 words per exception).
Increases stmhal code by 4 bytes, and decreases unix x64 code by 32
bytes.

This patch gives proper SyntaxError exceptions for bad global/nonlocal
declarations.  It also reduces code size: 304 bytes on unix x64, 132
bytes on stmhal.

Helps other ports.

This saves around 100 bytes code space on stmhal, more on unix.

This speeds up writes significantly.

Just adjust line-endings of micropython.exe output, the rest should be
handled by Wine (automagically on properly configured distro).

To run:

MICROPY_MICROPYTHON=../windows/micropython.exe ./run-tests

Adds just 60 bytes to stmhal binary.  Addresses issue #362.

This fixes FORCED_EXIT internal flag leaking into Windows exit code.

acoshf, asinhf, atanhf were added from musl.  mathsincos.c was
split up into its original, separate files (from newlibe-nano-2).
tan was added.

All of the important missing float functions are now implemented,
and pyboard now passes tests/float/math_fun.py (finally!).

N (mod 4) is 0..3

Name choosen per latest conventions and for compatibiity with stmhal port.

Addresses issue #1006.

Otherwise, new tests are forgotten to be added to explicit lists. Issue
found running on Debian/ARM.

You can now assign to the range end variable and the for-loop still
works correctly.  This fully addresses issue #565.

Also fixed a bug with the stack not being fully popped when breaking out
of an optimised for-loop (and it's actually impossible to write a test
for this case!).