Not creating explicit record locks will speed up the test.
Also, disable the use of InnoDB persistent statistics in the test of
MDEV-27270 to avoid intermittent failures in 10.6 or later
(after commit 9608773f75)
due to the nondeterministic scheduling of STATS_AUTO_PERSISTENT.
Let us specify STATS_AUTO_RECALC=0 for the failing section of the test.
It is possible that this test started failing sporadically ever since
commit 9608773f75 was applied and
tests no longer globally disable the InnoDB persistent statistics.
In main.index_merge_myisam we remove the test that was added in
commit a2d24def8c because
it duplicates the test case that was added in
commit 5af12e4635.
For a key with keyparts (k1,k2,k3) , if we are building a range over the keyparts
we should make sure that if min_value/max_value for a keypart is not added to
key buffer then the keyparts following should also not be allowed.
