MDEV-7895 - HANDLER READ doesn't upgrade metadata lock from S to SRbb-mdev7895

Change code for HANDLER READ statements to upgrade S metadata lock to
SR metadata lock for the duration of read. This allows us properly
isolate HANDLER READ from LOCK TABLES WRITE and makes metadata locking
for these statements consistent with locking for other DML.

HANDLER-related tests had to be adjusted to take into account that
HANDLER READ will wait for and acquire SR lock.

0 files changed, 0 insertions, 0 deletions