## What changes were proposed in this pull request?
Presto's implementation accepts arbitrary arrays of primitive types as an input:
```
presto> SELECT array_join(ARRAY [1, 2, 3], ', ');
_col0
---------
1, 2, 3
(1 row)
```
This PR proposes to implement a type coercion rule for ```array_join``` function that converts arrays of primitive as well as non-primitive types to arrays of string.
## How was this patch tested?
New test cases add into:
- sql-tests/inputs/typeCoercion/native/arrayJoin.sql
- DataFrameFunctionsSuite.scala
Author: Marek Novotny <mn.mikke@gmail.com>
Closes#21620 from mn-mikke/SPARK-24636.
e07aee2165