Remove .Wait() calls from tests

Remove unnecessary async keywords
Postfix methods returning a Task with "Async"

Fixes #5308

Author: AndriySvyryd

src/EFCore.Relational.Specification.Tests/MigrationsTestBase.cs

@@ -286,7 +286,7 @@ public virtual async Task Can_execute_operations()
             }
         }
 
-        protected virtual async Task ExecuteAsync(IServiceProvider services, Action<MigrationBuilder> buildMigration)
+        protected virtual Task ExecuteAsync(IServiceProvider services, Action<MigrationBuilder> buildMigration)
         {
             var generator = services.GetRequiredService<IMigrationsSqlGenerator>();
             var executor = services.GetRequiredService<IMigrationCommandExecutor>();
@@ -299,7 +299,7 @@ protected virtual async Task ExecuteAsync(IServiceProvider services, Action<Migr
 
             var commandList = generator.Generate(operations);
 
-            await executor.ExecuteNonQueryAsync(commandList, connection);
+            return executor.ExecuteNonQueryAsync(commandList, connection);
         }
 
         protected virtual void BuildFirstMigration(MigrationBuilder migrationBuilder)

src/EFCore.Specification.Tests/PropertyValuesTestBase.cs

@@ -1960,15 +1960,15 @@ private async Task NonGeneric_GetDatabaseValues_for_entity_not_in_the_store_retu
         }
 
         [Fact]
-        public virtual async Task GetDatabaseValues_for_derived_entity_not_in_the_store_returns_null()
+        public virtual Task GetDatabaseValues_for_derived_entity_not_in_the_store_returns_null()
         {
-            await GetDatabaseValues_for_derived_entity_not_in_the_store_returns_null_implementation(e => Task.FromResult(e.GetDatabaseValues()));
+            return GetDatabaseValues_for_derived_entity_not_in_the_store_returns_null_implementation(e => Task.FromResult(e.GetDatabaseValues()));
         }
 
         [Fact]
-        public virtual async Task GetDatabaseValuesAsync_for_derived_entity_not_in_the_store_returns_null()
+        public virtual Task GetDatabaseValuesAsync_for_derived_entity_not_in_the_store_returns_null()
         {
-            await GetDatabaseValues_for_derived_entity_not_in_the_store_returns_null_implementation(e => e.GetDatabaseValuesAsync());
+            return GetDatabaseValues_for_derived_entity_not_in_the_store_returns_null_implementation(e => e.GetDatabaseValuesAsync());
         }
 
         private async Task GetDatabaseValues_for_derived_entity_not_in_the_store_returns_null_implementation(