tests: Move tests/acpi-test-data/ to tests/data/acpi/

Currently tests/acpi-test-data contains data files used by the
bios-tables-test, and configure individually symlinks those
data files into the build directory using a wildcard.

Using a wildcard like this is a bad idea, because if a new
data file is added, nothing causes configure to be rerun,
and so no symlink is added for the new file. This can cause
tests to spuriously fail when they can't find their data.
Instead, it's better to symlink an entire directory of
data files. We already have such a directory: tests/data.

Move the data files from tests/acpi-test-data/ to
tests/data/acpi/, and remove the unnecessary symlinking.

We can remove entirely the note in rebuild-expected-aml.sh
about copying any new data files, because now they will
be in the source directory, not the build directory, and
no copying is required.

(We can't just change the existing tests/acpi-test-data/
to being a symlinked directory, because if we did that and
a developer switched git branches from one after that change
to one before it then configure would end up trashing all
the test files by making them symlinks to themselves.
Changing their path avoids this annoyance.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>