avro

AVRO-3495: Rust: Fields order should not matter (#1650)

* AVRO-3495: The order of the struct's fields and schema's fields should not matter

Signed-off-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>

* AVRO-3495: Use the lookup table when comparing values against fields by name

Until now it was expected that both the schema fields and the input
values are sorted the same way.

Use BTreeMap instead of HashMap for the lookup table because otherwise
the assertion on the validation error messages is impossible due to
random printing of the map's entries

Signed-off-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>

* AVRO-3495: Update the test case

Signed-off-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>