C#: Remove expanded assignments from tests.

Author: michaelnebel

csharp/ql/test/library-tests/assignments/AssignOperationExpanded.expected

@@ -1,5 +1,4 @@
 nullcoalescing
-| NullCoalescingAssignment.cs:8:9:8:18 | ... ?? ... |
 | NullableRefTypes.cs:94:17:94:25 | ... ?? ... |
 assignments
-| NullCoalescingAssignment.cs:8:9:8:18 | ... ??= ... | NullCoalescingAssignment.cs:8:9:8:18 | ... = ... |
+| NullCoalescingAssignment.cs:8:9:8:18 | ... ??= ... |

csharp/ql/test/library-tests/assignments/AssignOperationExpanded.ql

@@ -2,6 +2,4 @@ import csharp
 
 query predicate nullcoalescing(NullCoalescingExpr expr) { any() }
 
-query predicate assignments(AssignCoalesceExpr expr, Expr expanded) {
-  expanded = expr.getExpandedAssignment()
-}
+query predicate assignments(AssignCoalesceExpr expr) { any() }