bdiff: fold in shift calculation in normalize

This just makes the code harder to read without any performance
advantage. We're going to make the check here more complex, let's make
it simpler first.

mercurial/bdiff.c

@@ -259,22 +259,18 b' static int diff(struct line *a, int an, '
 	/* normalize the hunk list, try to push each hunk towards the end */
 	for (curr = base->next; curr; curr = curr->next) {
 		struct hunk *next = curr->next;
-		int shift = 0;
 
 		if (!next)
 			break;
 
 		if (curr->a2 == next->a1 || curr->b2 == next->b1)
-			while (curr->a2 + shift < an && curr->b2 + shift < bn
-			       && !cmp(a + curr->a2 + shift,
-				       b + curr->b2 + shift))
-				shift++;
-		if (!shift)
-			continue;
-		curr->b2 += shift;
-		next->b1 += shift;
-		curr->a2 += shift;
-		next->a1 += shift;
+			while (curr->a2 < an && curr->b2 < bn
+			       && !cmp(a + curr->a2, b + curr->b2)) {
+				curr->a2++;
+				next->a1++;
+				curr->b2++;
+				next->b1++;
+			}
 	}
 
 	for (curr = base->next; curr; curr = curr->next)