tests: scrap old automake based kernel test runner

Upstream broke our dynamic creation of the testlist, and I think
adding stupid .tests suffixes everywhere just to appease upstream
autohell tools isn't that great. So scrap it, we can use piglit
instead.

References: https://lists.gnu.org/archive/html/help-debbugs/2013-06/msg00000.html
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

README

@@ -24,17 +24,10 @@ tests/
 	changes.  Hopefully this can cover the relevant cases we need to
 	worry about, including backwards compatibility.
 
-	Run this tests with "make test" as root from this directory. Note that
-	no other drm clients (X server) may run.
-
-	"make test" only runs a default set of tests and is useful for
-	regression testing. Other tests not run are:
-	- tests that might hang the gpu, see HANG in Makefile.am
-	- gem_stress, a stress test suite. Look at the source for all the
-	  various options.
-	- testdisplay is only run in the default mode. testdisplay has tons of
-	  options to test different kms functionality, again read the source for
-	  the details.
+	Note: The old automake based testrunner had to be scraped due to
+	upstream changes which broke dynamic creation of the test list. Of
+	course it is still possible to directly run tests, even when not always
+	limiting tests to specific subtests (like piglit does).
 
 	The more comfortable way to run tests is with piglit. First grab piglit
 	from:
@@ -60,6 +53,15 @@ tests/
 
 	for some useful options.
 
+	Piglit only runs a default set of tests and is useful for regression
+	testing. Other tests not run are:
+	- tests that might hang the gpu, see HANG in Makefile.am
+	- gem_stress, a stress test suite. Look at the source for all the
+	  various options.
+	- testdisplay is only run in the default mode. testdisplay has tons of
+	  options to test different kms functionality, again read the source for
+	  the details.
+
 lib/
 	Common helper functions and headers used by the other tools.