### What changes were proposed in this pull request?
Provide the (configurable) ability to perform Avro-to-Catalyst schema field matching using the position of the fields instead of their names. A new `option` is added for the Avro datasource, `positionalFieldMatching`, which instructs `AvroSerializer`/`AvroDeserializer` to perform positional field matching instead of matching by name.
### Why are the changes needed?
This by-name matching is somewhat recent; prior to PR #24635, at least on the write path, schemas were matched by positionally ("structural" comparison). While by-name is better behavior as a default, it will be better to make this configurable by a user. Even at the time that PR #24635 was handled, there was [interest in making this behavior configurable](https://github.com/apache/spark/pull/24635#issuecomment-494205251), but it appears it went unaddressed.
There is precedence for configurability of this behavior as seen in PR #29737, which added this support for ORC. Besides this precedence, the behavior of Hive is to perform matching positionally ([ref](https://cwiki.apache.org/confluence/display/Hive/AvroSerDe#AvroSerDe-WritingtablestoAvrofiles)), so this is behavior that Hadoop/Hive ecosystem users are familiar with.
### Does this PR introduce _any_ user-facing change?
Yes, a new option is provided for the Avro datasource, `positionalFieldMatching`, which provides compatibility with Hive and pre-3.0.0 Spark behavior.
### How was this patch tested?
New unit tests are added within `AvroSuite`, `AvroSchemaHelperSuite`, and `AvroSerdeSuite`; and most of the existing tests within `AvroSerdeSuite` are adapted to perform the same test using by-name and positional matching to ensure feature parity.
Closes#31490 from xkrogen/xkrogen-SPARK-34365-avro-positional-field-matching.
Authored-by: Erik Krogen <xkrogen@apache.org>
Signed-off-by: Gengliang Wang <gengliang@apache.org>
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