These tests are intended to improve coverage and provide a record of
behaviour that's either not implemented or non-compliant to CPython.

Which are currently intermixed with real scripts and spread around various
dirs.

Just dependent micropython-lib modules update for upip, no new
functionality.

Was KeyError, should be ValueError.

If byteorder of MicroPython under test and host CPython differ.

Indeed, this flag efectively selects architecture target, and must
consistently apply to all compiles and links, including 3rd-party
libraries, unlike CFLAGS, which have MicroPython-specific setting.

Some libc's may implement tgammaf as a header macro using tgamma(), so
don't assume it'll be in the library.

Latest Arch Linux doesn't have libm.so as a proper shared object and so
we need to load libm.so.6.

Also, hint about possibility to adjust heap size.

Saves 320 bytes on x86.

unix-cpy was originally written to get semantic equivalent with CPython
without writing functional tests.  When writing the initial
implementation of uPy it was a long way between lexer and functional
tests, so the half-way test was to make sure that the bytecode was
correct.  The idea was that if the uPy bytecode matched CPython 1-1 then
uPy would be proper Python if the bytecodes acted correctly.  And having
matching bytecode meant that it was less likely to miss some deep
subtlety in the Python semantics that would require an architectural
change later on.

But that is all history and it no longer makes sense to retain the
ability to output CPython bytecode, because:

1. It outputs CPython 3.3 compatible bytecode.  CPython's bytecode
changes from version to version, and seems to have changed quite a bit
in 3.5.  There's no point in changing the bytecode output to match
CPython anymore.

2. uPy and CPy do different optimisations to the bytecode which makes it
harder to match.

3. The bytecode tests are not run.  They were never part of Travis and
are not run locally anymore.

4. The EMIT_CPYTHON option needs a lot of extra source code which adds
heaps of noise, especially in compile.c.

5. Now that there is an extensive test suite (which tests functionality)
there is no need to match the bytecode.  Some very subtle behaviour is
tested with the test suite and passing these tests is a much better
way to stay Python-language compliant, rather than trying to match
CPy bytecode.

The nss param in the pyboard has a different meaning that doesn't
apply to the WiPy.