malloc: checked_request2size failure deadlocks

malloc: checked_request2size failure deadlocks

For some rarely cases(almost App bugs), calling malloc with
a very largre size, checked_request2size check will fail,set
ENOMEM, and return 0 to caller.

But this will let __malloc_lock futex locked and owned by the
caller. In multithread circumstance, other thread calling
malloc/calloc will NOT succeed and get locked.

Signed-off-by: Zhiqiang Zhang <zhangzhiqiang.zhang@huawei.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>