Fix duplicate join for collection (#2890)

Author: bahusoid

src/NHibernate.Test/Async/NHSpecificTest/GH1962/Fixture.cs

@@ -19,11 +19,9 @@ namespace NHibernate.Test.NHSpecificTest.GH1962
 	public class FixtureAsync : BugTestCase
 	{
 		[Test]
-		[KnownBug("#1962")]
 		public async Task LinqShouldBeValidAsync()
 		{
 			using (var session = OpenSession())
-			using (session.BeginTransaction())
 			{
 				var result =
 					await (session

src/NHibernate.Test/NHSpecificTest/GH1962/Fixture.cs

@@ -7,11 +7,9 @@ namespace NHibernate.Test.NHSpecificTest.GH1962
 	public class Fixture : BugTestCase
 	{
 		[Test]
-		[KnownBug("#1962")]
 		public void LinqShouldBeValid()
 		{
 			using (var session = OpenSession())
-			using (session.BeginTransaction())
 			{
 				var result =
 					session

src/NHibernate/Hql/Ast/ANTLR/Tree/FromElementFactory.cs

@@ -362,6 +362,7 @@ private FromElement CreateEntityAssociation(
 				_fromClause.Walker.AddQuerySpaces(_queryableCollection.CollectionSpaces);
 			}
 			elem.CollectionTableAlias = roleAlias;
+			_fromClause.AddCollectionJoinFromElementByPath(_path, elem);
 			return elem;
 		}