Add explanation for disabled WGPU tests (shader-slang#5628)

Author: aleino-nv

tests/compute/global-type-param-in-entrypoint.slang

@@ -1,3 +1,4 @@
+// tests/compute/*type-param* tests are broken #5627
 //DISABLED_TEST(compute):COMPARE_RENDER_COMPUTE: -shaderobj
 
 //TEST_INPUT: cbuffer(data=[1.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 0.0 1.0]):name Uniforms

tests/compute/texture-sample-grad-offset-clamp.slang

@@ -1,5 +1,6 @@
 //TEST(compute, vulkan):COMPARE_RENDER_COMPUTE:-vk -shaderobj -render-feature shader-resource-min-lod
 //TEST(compute):COMPARE_RENDER_COMPUTE:-shaderobj -render-feature shader-resource-min-lod
+// WGSL: There is no SampleGrad taking a LOD-clamp parameter in
 
 //TEST_INPUT: Texture2D(size=4, content = one):name=t2D
 //TEST_INPUT: Sampler:name=samplerState

tests/compute/type-param-varying.slang

@@ -1,3 +1,4 @@
+// tests/compute/*type-param* tests are broken #5627
 //DISABLED_TEST(compute):COMPARE_RENDER_COMPUTE:
 
 //TEST_INPUT: global_type AssembledVertex