Auto-generate X8 LUT microkernels and tests

PiperOrigin-RevId: 395630360
diff --git a/BUILD.bazel b/BUILD.bazel
index b01c236..955616a 100644
--- a/BUILD.bazel
+++ b/BUILD.bazel
@@ -287,7 +287,7 @@
     "src/u8-maxpool/9p8x-minmax-scalar-c1.c",
     "src/u8-rmax/scalar.c",
     "src/u8-vclamp/scalar-x4.c",
-    "src/x8-lut/scalar.c",
+    "src/x8-lut/gen/lut-scalar-x4.c",
     "src/x8-zip/x2-scalar.c",
     "src/x8-zip/x3-scalar.c",
     "src/x8-zip/x4-scalar.c",
@@ -899,7 +899,11 @@
     "src/u8-maxpool/9p8x-minmax-scalar-c1.c",
     "src/u8-rmax/scalar.c",
     "src/u8-vclamp/scalar-x4.c",
-    "src/x8-lut/scalar.c",
+    "src/x8-lut/gen/lut-scalar-x1.c",
+    "src/x8-lut/gen/lut-scalar-x2.c",
+    "src/x8-lut/gen/lut-scalar-x4.c",
+    "src/x8-lut/gen/lut-scalar-x8.c",
+    "src/x8-lut/gen/lut-scalar-x16.c",
     "src/x8-zip/x2-scalar.c",
     "src/x8-zip/x3-scalar.c",
     "src/x8-zip/x4-scalar.c",