Use dynamic length in blocked_terms_unittest

For the blocked test instances we should always see the same number of failures
as the number of lines, so we can just count that instead of having an extra
constant.

BUG=None
TEST=./blocked_terms_unittest.py

Change-Id: Icef38ff53a5bc1dc761421a50826b47b9ca0fd6e
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/repohooks/+/2522915
Reviewed-by: Daisuke Nojiri <dnojiri@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Bernie Thompson <bhthompson@chromium.org>
Tested-by: Bernie Thompson <bhthompson@chromium.org>
diff --git a/blocked_terms_unittest.py b/blocked_terms_unittest.py
index 499e5ba..5c14b58 100755
--- a/blocked_terms_unittest.py
+++ b/blocked_terms_unittest.py
@@ -93,8 +93,8 @@
                     (3, 'blocked .mitm'),
                     (4, 'blocked MITM'),
                     (5, 'blocked mitm1'),],
-        self.MATCH: 5,
     }
+    test_instance_blocked[self.MATCH] = len(test_instance_blocked[self.DIFF])
     self.CheckKeyword(test_instance_blocked)
 
     test_instance_unblocked = {
@@ -113,8 +113,8 @@
                     (5, 'blocked sane1'),
                     (6, 'blocked insane'),
                     (7, 'blocked .insane'),],
-        self.MATCH: 7,
     }
+    test_instance_blocked[self.MATCH] = len(test_instance_blocked[self.DIFF])
     self.CheckKeyword(test_instance_blocked)
 
     test_instance_unblocked = {
@@ -131,8 +131,8 @@
                     (4, 'blocked _whitelist'),
                     (5, 'blocked whitelist1'),
                     (6, 'blocked whitelisted'),],
-        self.MATCH: 6,
     }
+    test_instance_blocked[self.MATCH] = len(test_instance_blocked[self.DIFF])
     self.CheckKeyword(test_instance_blocked)
 
     test_instance_unblocked = {