Annotated OpenType Specification or aots, https://github.com/adobe-type-tools/aots
provides a set of tests for OpenType specification, this change add those tests in addition
to modified version of their HarfBuzz test runner for generating harfbuzz project specific tests.
For the API tests, output the test programs at $(TOP_BUILDDIR) so that
the freshly-built DLLs will be available for the test programs. For
those that are run through the Python wrapper scripts, use
${PYTHON_EXECUTABLE} instead of plain 'python' in case the Python
interpreter is not in the PATH.