patch 8.2.5004: right shift on negative number does not work as documented

Problem:    Right shift on negative number does not work as documented.
Solution:   Use a uvarnumber_T type cast.
diff --git a/src/vim9expr.c b/src/vim9expr.c
index c84be87..3e720d9 100644
--- a/src/vim9expr.c
+++ b/src/vim9expr.c
@@ -2719,11 +2719,8 @@
 	    else if (type == EXPR_LSHIFT)
 		tv1->vval.v_number = tv1->vval.v_number << tv2->vval.v_number;
 	    else
-	    {
-		tv1->vval.v_number = tv1->vval.v_number >> tv2->vval.v_number;
-		// clear the topmost sign bit
-		tv1->vval.v_number &= ~((uvarnumber_T)1 << MAX_LSHIFT_BITS);
-	    }
+		tv1->vval.v_number =
+			(uvarnumber_T)tv1->vval.v_number >> tv2->vval.v_number;
 	    clear_tv(tv2);
 	    --ppconst->pp_used;
 	}