dev-python/clang-python: Fix handling test failures

Fix handling test failurse to die on any implementation failing, rather
than only on the last one tested.

dev-python/clang-python/clang-python-6.0.9999.ebuild

@@ -36,8 +36,12 @@ src_unpack() {
 	git-r3_checkout '' '' '' bindings/python
 }
 
+python_test() {
+	"${EPYTHON}" -m unittest discover -v || die "Tests fail with ${EPYTHON}"
+}
+
 src_test() {
-	python_foreach_impl python -m unittest discover -v || die
+	python_foreach_impl python_test
 }
 
 src_install() {