[tools]: Generate intrinisic test cases

Add test/intrinsics/intrinsics.wgsl.tmpl that generates a vast set of intrinsic overload permutations into test/intrinsics/gen/...

Add expected output for all of these, including 'SKIP' headers for those that currently fail.

Fixed: tint:832
Change-Id: Id6888df52c07f35e7a55199f2ad4d842c6e2595c
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/53051
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: David Neto <dneto@google.com>
diff --git a/test/intrinsics/gen/abs/4ad288.wgsl.expected.wgsl b/test/intrinsics/gen/abs/4ad288.wgsl.expected.wgsl
new file mode 100644
index 0000000..2842caf
--- /dev/null
+++ b/test/intrinsics/gen/abs/4ad288.wgsl.expected.wgsl
@@ -0,0 +1,18 @@
+fn abs_4ad288() {
+  var res : i32 = abs(1);
+}
+
+[[stage(vertex)]]
+fn vertex_main() {
+  abs_4ad288();
+}
+
+[[stage(fragment)]]
+fn fragment_main() {
+  abs_4ad288();
+}
+
+[[stage(compute)]]
+fn compute_main() {
+  abs_4ad288();
+}