d/tests: Add superficial autopkgtests

The glslang-dev test is not at all thorough, but it should detect at
least some changes to the build machinery and dependencies that would
otherwise make dependent packages like renderdoc FTBFS.

Similarly, the glslang-tools test just screen-scrapes the --help output
rather than verifying that a real shader can be compiled, but that's
better than nothing.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Closes: #940488