Validate that in/out storage classes are not used

Use a DisableValidationDecoration to allow these storage classes only
for variables generated by the SPIR-V sanitizer.

Fix or delete all of the tests that were wrongly using these storage
classes.

Bug: tint:697
Change-Id: Ife1154f687b18529cfcc7a0ed93407fd25c9868e
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/55404
Reviewed-by: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Auto-Submit: James Price <jrprice@google.com>
Commit-Queue: James Price <jrprice@google.com>

src/ast/disable_validation_decoration.cc

@@ -34,8 +34,8 @@ std::string DisableValidationDecoration::InternalName() const {
       return "disable_validation__function_has_no_body";
     case DisabledValidation::kBindingPointCollision:
       return "disable_validation__binding_point_collision";
-    case DisabledValidation::kFunctionVarStorageClass:
-      return "disable_validation__function_var_storage_class";
+    case DisabledValidation::kIgnoreStorageClass:
+      return "disable_validation__ignore_storage_class";
     case DisabledValidation::kEntryPointParameter:
       return "disable_validation__entry_point_parameter";
   }

src/ast/disable_validation_decoration.h

@@ -31,9 +31,9 @@ enum class DisabledValidation {
   /// When applied to a module-scoped variable, the validator will not complain
   /// if two resource variables have the same binding points.
   kBindingPointCollision,
-  /// When applied to a function-scoped variable, the validator will not
-  /// complain if the storage class is not `function`.
-  kFunctionVarStorageClass,
+  /// When applied to a variable, the validator will not complain about the
+  /// declared storage class.
+  kIgnoreStorageClass,
   /// When applied to an entry-point function parameter, the validator will not
   /// check for entry IO decorations.
   kEntryPointParameter,