[tint] Implement support for r8unorm

Bug: dawn:2101
Change-Id: I0ebb48c577f114efd9e2564ac818c4869852a927
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/176042
Reviewed-by: James Price <jrprice@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
diff --git a/test/tint/builtins/gen/literal/textureSampleCompareLevel/4cf3a2.wgsl.expected.glsl b/test/tint/builtins/gen/literal/textureSampleCompareLevel/4cf3a2.wgsl.expected.glsl
index d2bd75c..c34ffd2 100644
--- a/test/tint/builtins/gen/literal/textureSampleCompareLevel/4cf3a2.wgsl.expected.glsl
+++ b/test/tint/builtins/gen/literal/textureSampleCompareLevel/4cf3a2.wgsl.expected.glsl
@@ -35,6 +35,7 @@
 
 #version 310 es
 precision highp float;
+precision highp int;
 
 uniform highp samplerCubeArrayShadow arg_0_arg_1;
 
@@ -56,8 +57,8 @@
   return;
 }
 error: Error parsing GLSL shader:
-ERROR: 0:4: 'samplerCubeArrayShadow' : Reserved word. 
-ERROR: 0:4: '' : compilation terminated 
+ERROR: 0:5: 'samplerCubeArrayShadow' : Reserved word. 
+ERROR: 0:5: '' : compilation terminated 
 ERROR: 2 compilation errors.  No code generated.