Mismatch of schemas on the storage and in the net_box connection

[GRISHNOV]

In the course of solving the issue with mismatch of schemas on the storage and in the net_box connection on router through patch, some problems were discovered. If there is a need to calculating the hash of the schema to determine if schema_reload is necessary, there may be false positive mismatches:

• Potential problem with hashing approach on different hosts: Possible schema hashing false mismatch due to unstable msgpack map serialization #360
• Nuance with the need to set the default exclude_null value: Default false value of exclude_null is present through net.box but not locally tarantool#8649

And separately for tarantool v1:

• net.box's schema always states index as non-unique. Related issue, which was not backported to tarantool v1.
• Information about collation is described in different ways via net.box for router and locally via box on the storage. Related issue.