WL#8893: InnoDB: Remove the deprecated parameter innodb_checksums

In MySQL 5.6.3 and higher, innodb_checksums is deprecated, replaced by
innodb_checksum_algorithm. So, we need to remove the innodb_checksums parameter.

The option innodb_checksums was deprecated as part of "WL#5652 InnoDB: Use HW
CRC32".  Since the functionality provided by innodb_checksums is a subset of
what is provided by innodb_checksum_algorithm, it was deprecated.  

One test case along with its result file has been removed:

 delete mode 100644 mysql-test/suite/sys_vars/r/innodb_checksums_basic.result
 delete mode 100644 mysql-test/suite/sys_vars/t/innodb_checksums_basic.test