patch 9.0.1792: problem with gj/gk/gM and virtual text

Problem:  Normal mode "gM", "gj", "gk" commands behave incorrectly with
          virtual text.
Solution: Use linetabsize() instead of linetabsize_str().

closes: #12909

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: zeertzjq <zeertzjq@outlook.com>
diff --git a/src/normal.c b/src/normal.c
index 38229e9..b73afd3 100644
--- a/src/normal.c
+++ b/src/normal.c
@@ -2304,7 +2304,7 @@
     static int
 nv_screengo(oparg_T *oap, int dir, long dist)
 {
-    int		linelen = linetabsize_str(ml_get_curline());
+    int		linelen = linetabsize(curwin, curwin->w_cursor.lnum);
     int		retval = OK;
     int		atend = FALSE;
     int		n;
@@ -2374,7 +2374,7 @@
 		}
 		cursor_up_inner(curwin, 1);
 
-		linelen = linetabsize_str(ml_get_curline());
+		linelen = linetabsize(curwin, curwin->w_cursor.lnum);
 		if (linelen > width1)
 		    curwin->w_curswant += (((linelen - width1 - 1) / width2)
 								+ 1) * width2;
@@ -2411,7 +2411,7 @@
 		// clipped to column 0.
 		if (curwin->w_curswant >= width1)
 		    curwin->w_curswant -= width2;
-		linelen = linetabsize_str(ml_get_curline());
+		linelen = linetabsize(curwin, curwin->w_cursor.lnum);
 	    }
 	}
       }
@@ -6052,7 +6052,7 @@
 	{
 	    oap->motion_type = MCHAR;
 	    oap->inclusive = FALSE;
-	    i = linetabsize_str(ml_get_curline());
+	    i = linetabsize(curwin, curwin->w_cursor.lnum);
 	    if (cap->count0 > 0 && cap->count0 <= 100)
 		coladvance((colnr_T)(i * cap->count0 / 100));
 	    else