We should not need anywhere near 32 bits of entropy, so we might
just limit ourselves to a 32-bit random number generator.

Also, it might be cheaper to use exclusive-or, bit shifting and
conditional jumps, instead of multiplication and addition.

We use relaxed atomic operations on the global random number generator
state in order in an attempt to silence any warnings about race conditions.
There is an obvious race condition between the load and store in
ut_rnd_gen(), but we do not think that it matters much that the
state of the random number generator could 'stutter'.

This change seems makes the 'uncompress_ops' nondeterministic
in innodb_zip.cmp_per_index after the restart. It looks like
there is an inherent race condition in the test, because the
table could be opened for InnoDB statistics recalculation
already before innodb_cmp_per_index_enabled was set. We might
end up having uncompress_ops anywhere between 0 and 9, or perhaps
even more. Let us remove that part of the test.

- If select query chooses the index 'b' over clustered index then the issue
can happen. Changed the test case to use primary index for the select
query.

information_schema. Added .opt file to enable running this
test as a part of innodb_zip suite and recorded current
correct results.

Contains also

MDEV-10547: Test multi_update_innodb fails with InnoDB 5.7

	The failure happened because 5.7 has changed the signature of
	the bool handler::primary_key_is_clustered() const
	virtual function ("const" was added). InnoDB was using the old
	signature which caused the function not to be used.

MDEV-10550: Parallel replication lock waits/deadlock handling does not work with InnoDB 5.7

	Fixed mutexing problem on lock_trx_handle_wait. Note that
	rpl_parallel and rpl_optimistic_parallel tests still
	fail.

MDEV-10156 : Group commit tests fail on 10.2 InnoDB (branch bb-10.2-jan)
  Reason: incorrect merge

MDEV-10550: Parallel replication can't sync with master in InnoDB 5.7 (branch bb-10.2-jan)
  Reason: incorrect merge