Rename Q8 microkernels and operators to QU8

- Indicate unsigned datatype
- Make space for QS8 with signed quantization

PiperOrigin-RevId: 321275708
diff --git a/test/qu8-igemm-minmax.yaml b/test/qu8-igemm-minmax.yaml
new file mode 100644
index 0000000..e329d58
--- /dev/null
+++ b/test/qu8-igemm-minmax.yaml
@@ -0,0 +1,12 @@
+# Copyright 2019 Google LLC
+#
+# This source code is licensed under the BSD-style license found in the
+# LICENSE file in the root directory of this source tree.
+- name: xnn_qu8_igemm_minmax_ukernel_4x8__neon
+  k-block: 8
+- name: xnn_qu8_igemm_minmax_ukernel_8x8__neon
+  k-block: 8
+- name: xnn_qu8_igemm_minmax_ukernel_4x4c2__sse2
+  k-block: 8
+- name: xnn_qu8_igemm_minmax_ukernel_2x2__scalar
+  k-block: 1