patch 9.0.1997: Some unused code in move.c and string.c

Problem:  Some unused code in move.c and string.c
Solution: Remove it

closes: #13288

Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: dundargoc <gocdundar@gmail.com>
diff --git a/src/strings.c b/src/strings.c
index 33616d6..c04cbe8 100644
--- a/src/strings.c
+++ b/src/strings.c
@@ -2596,7 +2596,7 @@
 		    CHECK_POS_ARG;
 		}
 	    }
-	    else if (VIM_ISDIGIT((int)(*(arg = p))))
+	    else if (VIM_ISDIGIT((int)(*p)))
 	    {
 		// size_t could be wider than unsigned int; make sure we treat
 		// argument like common implementations do
@@ -2651,7 +2651,7 @@
 			CHECK_POS_ARG;
 		    }
 		}
-		else if (VIM_ISDIGIT((int)(*(arg = p))))
+		else if (VIM_ISDIGIT((int)(*p)))
 		{
 		    // size_t could be wider than unsigned int; make sure we
 		    // treat argument like common implementations do
@@ -2684,7 +2684,7 @@
 		if (length_modifier == 'l' && *p == 'l')
 		{
 		    // double l = __int64 / varnumber_T
-		    length_modifier = 'L';
+		    // length_modifier = 'L';
 		    p++;
 		}
 	    }