tests/functional: skip memaddr tests on 32-bit builds

tests/functional: skip memaddr tests on 32-bit builds

If the QEMU binary was built for a 32-bit ELF target we cannot run the
memory address space tests as they all require ability to address more
RAM that can be represented on 32-bit.

We can't use a decorator to skip the tests as we need setUp() to run to
pick the QEMU binary, thus we must call a method at the start of each
test to check and skip it. The functional result is effectively the
same as using a decorator, just less pretty. This code will go away when
32-bit hosts are full dropped from QEMU.

The code allows any non-ELF target since all macOS versions supported
at 64-bit only and we already dropped support for 32-bit Windows.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-ID: <20250228102738.3064045-6-berrange@redhat.com>
[thuth: Add missing byteorder='little' to from_bytes()]
Signed-off-by: Thomas Huth <thuth@redhat.com>