Remove outdated test.

We now support lookup joins in subqueries. This test only happened to work because of a specific interaction with StripRowNodes, which no longer exist.

go/libraries/doltcore/sqle/kvexec/lookup_join_test.go

@@ -110,15 +110,6 @@ func TestLookupJoin(t *testing.T) {
 			join:      "select  /*+ LOOKUP_JOIN(xy,ab) */ * from xy join ab on x = a",
 			doRowexec: false,
 		},
-		{
-			name: "reject join in subquery with non-nil scope",
-			setup: []string{
-				"create table xy (x int primary key, y int)",
-				"create table ab (a int primary key, b int)",
-			},
-			join:      "select  1, (select /*+ LOOKUP_JOIN(xy,ab) */ count(*) from xy join ab on x = a) cnt",
-			doRowexec: false,
-		},
 		{
 			name: "reject complex join expression",
 			setup: []string{