resolver: Temporarily disable vertex position validation

CTS needs updating to fix this validation error, and this is blocking autorolls for tint and dawn.

Change-Id: Ie3aaa37f0914fdb39099e7c15e65be0bcca0677a
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/48682
Reviewed-by: James Price <jrprice@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>

src/resolver/entry_point_validation_test.cc

@@ -500,7 +500,9 @@ TEST_F(ResolverEntryPointValidationTest, Parameter_Struct_DuplicateLocation) {
 12:34 note: while analysing entry point main)");
 }
 
-TEST_F(ResolverEntryPointValidationTest, VertexShaderMustReturnPosition) {
+// TODO(bclayton): Reenable after CTS is updated
+TEST_F(ResolverEntryPointValidationTest,
+       DISABLED_VertexShaderMustReturnPosition) {
   // [[stage(vertex)]]
   // fn main() {}
   Func(Source{{12, 34}}, "main", {}, ty.void_(), {},

src/resolver/resolver.cc

@@ -811,7 +811,8 @@ bool Resolver::ValidateEntryPoint(const ast::Function* func,
         }
       }
     }
-    if (!found) {
+    // TODO(bclayton): Reenable after CTS is updated
+    if (((false)) && !found) {
       diagnostics_.add_error(
           "a vertex shader must include the 'position' builtin in its return "
           "type",