Fix tests since non-warning diagnostics are reported with /warn:0

src/EditorFeatures/CSharpTest/Diagnostics/SimplifyTypeNames/SimplifyTypeNamesTests.cs

@@ -3995,25 +3995,8 @@ void Main()
                 options: PreferIntrinsicTypeInMemberAccess);
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsSimplifyTypeNames)]
-        [WorkItem(20377, "https://github.com/dotnet/roslyn/issues/20377")]
-        public async Task TestWarningLevel0()
-        {
-            // Ideally we would also want features to work with /warn:0, but this causes a compatibility conflict since
-            // /warn:0 can be used to suppress warnings with /warnaserror enabled.
-            await TestMissingInRegularAndScriptAsync(
-@"using System;
-
-namespace Root
-{
-    class A
-    {
-        [|System.Exception|] c;
-    }
-}", new TestParameters(compilationOptions: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary, warningLevel: 0)));
-        }
-
         [Theory]
+        [InlineData(0)]
         [InlineData(1)]
         [InlineData(2)]
         [InlineData(3)]
@@ -4052,6 +4035,10 @@ private async Task TestWithPredefinedTypeOptionsAsync(string code, string expect
             SingleOption(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInDeclaration, true, NotificationOption.Error),
             SingleOption(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInMemberAccess, this.onWithError, GetLanguage()));
 
+        private IDictionary<OptionKey, object> PreferIntrinsicTypeEverywhereAsWarning => OptionsSet(
+            SingleOption(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInDeclaration, true, NotificationOption.Warning),
+            SingleOption(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInMemberAccess, this.onWithWarning, GetLanguage()));
+
         private IDictionary<OptionKey, object> PreferIntrinsicTypeInDeclaration => OptionsSet(
             SingleOption(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInDeclaration, true, NotificationOption.Error),
             SingleOption(CodeStyleOptions.PreferIntrinsicPredefinedTypeKeywordInMemberAccess, this.offWithNone, GetLanguage()));

src/EditorFeatures/CSharpTest/RemoveUnnecessaryImports/RemoveUnnecessaryImportsTests.cs

@@ -1354,26 +1354,8 @@ static void Main(string[] args)
 }");
         }
 
-        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsRemoveUnnecessaryImports)]
-        [WorkItem(20377, "https://github.com/dotnet/roslyn/issues/20377")]
-        public async Task TestWarningLevel0()
-        {
-            // Ideally we would also want features to work with /warn:0, but this causes a compatibility conflict since
-            // /warn:0 can be used to suppress warnings with /warnaserror enabled.
-            await TestMissingInRegularAndScriptAsync(
-@"[|using System;
-using System.Collections.Generic;
-using System.Linq;
-
-class Program
-{
-    static void Main(string[] args)
-    {
-    }
-}|]", new TestParameters(compilationOptions: new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary, warningLevel: 0)));
-        }
-
         [Theory]
+        [InlineData(0)]
         [InlineData(1)]
         [InlineData(2)]
         [InlineData(3)]