patch 9.1.0163: Calling STRLEN() to compute ml_line_textlen when not needed

Problem:  Calling STRLEN() to compute ml_line_textlen when not needed.
Solution: Use 0 when STRLEN() will be required and call STRLEN() later.
          (zeertzjq)

closes: #14155

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/edit.c b/src/edit.c
index 998647c..26853dc 100644
--- a/src/edit.c
+++ b/src/edit.c
@@ -5088,7 +5088,7 @@
 			vim_free(curbuf->b_ml.ml_line_ptr);
 		    curbuf->b_ml.ml_line_ptr = newp;
 		    curbuf->b_ml.ml_line_len -= i;
-		    curbuf->b_ml.ml_line_textlen = (int)STRLEN(newp) + 1;
+		    curbuf->b_ml.ml_line_textlen = 0;
 		    curbuf->b_ml.ml_flags =
 			   (curbuf->b_ml.ml_flags | ML_LINE_DIRTY) & ~ML_EMPTY;
 		}