innodb.innodb_corrupt_bit test is unstable

On 5.5 trunk ASan:

innodb.innodb_corrupt_bit w2 [ fail ]
        Test ended at 2016-07-26 15:40:44

CURRENT_TEST: innodb.innodb_corrupt_bit
mysqltest: At line 78: query 'INSERT INTO corrupt_bit_test_ā VALUES(13000,'x',1,1)' failed: 1062: Duplicate entry '1-x' for key 'idxā'

The result from queries just before the failure was:
< snip >
select @@unique_checks;
@@unique_checks
0
select @@innodb_change_buffering_debug;
@@innodb_change_buffering_debug
1
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+1,z+1 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+10,z+10 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+20,z+20 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+50,z+50 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+100,z+100 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+200,z+200 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+400,z+400 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+800,z+800 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+1600,z+1600 FROM corrupt_bit_test_ā;
INSERT INTO corrupt_bit_test_ā SELECT 0,b,c+4000,z+4000 FROM corrupt_bit_test_ā;
select count(*) from corrupt_bit_test_ā;
count(*)
1024
CREATE INDEX idx3 ON corrupt_bit_test_ā(b, c);

More results from queries before failure can be found in /mnt/workspace/percona-server-5.5-asan-param/BUILD_TYPE/debug-asan/Host/ubuntu-xenial-64bit/mysql-test/var/2/log/innodb_corrupt_bit.log

The fix would be backporting

commit cae6d31ba34aabc930223db93f90bc27b991a6f1
Author: Jimmy Yang <email address hidden>
Date: Wed Dec 19 18:02:23 2012 +0800

    fix Bug #13430919 - GENERATE STABLE DUP KEY SCENARIO FOR
    INNODB.INNODB_CORRUPT_BIT

    rb://1759 approved by Marko