fix some nullables in tests

Author: SimonCropp

src/Polly.Specs/Bulkhead/BulkheadAsyncSpecs.cs

@@ -41,7 +41,7 @@ public void Should_throw_when_maxQueuingActions_less_than_zero()
     public void Should_throw_when_onBulkheadRejected_is_null()
     {
         Action policy = () => Policy
-            .BulkheadAsync(1, 0, null);
+            .BulkheadAsync(1, 0, null!);
 
         policy.Should().Throw<ArgumentNullException>().And
             .ParamName.Should().Be("onBulkheadRejectedAsync");

src/Polly.Specs/Bulkhead/BulkheadSpecs.cs

@@ -39,7 +39,7 @@ public void Should_throw_when_maxqueuedactions_less_than_zero()
     public void Should_throw_when_onBulkheadRejected_is_null()
     {
         Action policy = () => Policy
-            .Bulkhead(1, 0, null);
+            .Bulkhead(1, 0, null!);
 
         policy.Should().Throw<ArgumentNullException>().And
             .ParamName.Should().Be("onBulkheadRejected");

src/Polly.Specs/Bulkhead/BulkheadTResultAsyncSpecs.cs

@@ -42,7 +42,7 @@ public void Should_throw_when_maxQueuingActions_less_than_zero()
     public void Should_throw_when_onBulkheadRejected_is_null()
     {
         Action policy = () => Policy
-            .BulkheadAsync<int>(1, 0, null);
+            .BulkheadAsync<int>(1, 0, null!);
 
         policy.Should().Throw<ArgumentNullException>().And
             .ParamName.Should().Be("onBulkheadRejectedAsync");

src/Polly.Specs/Bulkhead/BulkheadTResultSpecs.cs

@@ -42,7 +42,7 @@ public void Should_throw_when_maxQueuingActions_less_than_zero()
     public void Should_throw_when_onBulkheadRejected_is_null()
     {
         Action policy = () => Policy
-            .Bulkhead<int>(1, 0, null);
+            .Bulkhead<int>(1, 0, null!);
 
         policy.Should().Throw<ArgumentNullException>().And
             .ParamName.Should().Be("onBulkheadRejected");

src/Polly.Specs/Helpers/Custom/AddBehaviourIfHandle/AddBehaviourIfHandleEngine.cs

@@ -27,7 +27,7 @@ internal static TResult Implementation<TResult>(
         }
         catch (Exception ex)
         {
-            Exception handledException = shouldHandleExceptionPredicates.FirstMatchOrDefault(ex);
+            Exception? handledException = shouldHandleExceptionPredicates.FirstMatchOrDefault(ex);
             if (handledException == null)
             {
                 throw;

src/Polly.Specs/Helpers/Custom/AddBehaviourIfHandle/AsyncAddBehaviourIfHandleEngine.cs

@@ -29,7 +29,7 @@ internal static async Task<TResult> ImplementationAsync<TResult>(
         }
         catch (Exception ex)
         {
-            Exception handledException = shouldHandleExceptionPredicates.FirstMatchOrDefault(ex);
+            Exception? handledException = shouldHandleExceptionPredicates.FirstMatchOrDefault(ex);
             if (handledException == null)
             {
                 throw;