tint: End-to-end tests for f16 built-in

This patch add Tint end-to-end tests for built-ins using f16 types.

Bug: tint:1473, tint:1502
Change-Id: I09db6e0b7e90541fb246e11d475e27be96a6d07e
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/97340
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Zhaoming Jiang <zhaoming.jiang@intel.com>
diff --git a/test/tint/builtins/gen/literal/log/cdbdc1.wgsl.expected.wgsl b/test/tint/builtins/gen/literal/log/cdbdc1.wgsl.expected.wgsl
new file mode 100644
index 0000000..645ccf9
--- /dev/null
+++ b/test/tint/builtins/gen/literal/log/cdbdc1.wgsl.expected.wgsl
@@ -0,0 +1,21 @@
+enable f16;
+
+fn log_cdbdc1() {
+  var res : vec4<f16> = log(vec4<f16>(f16()));
+}
+
+@vertex
+fn vertex_main() -> @builtin(position) vec4<f32> {
+  log_cdbdc1();
+  return vec4<f32>();
+}
+
+@fragment
+fn fragment_main() {
+  log_cdbdc1();
+}
+
+@compute @workgroup_size(1)
+fn compute_main() {
+  log_cdbdc1();
+}