Formatter: New options for new lines within array initializer braces

Right now, for new lines _within_ array initializers, there's only the two toggles: "After opening brace of array initializer" and "Before closing brace of array initializer".
What I would like specifically is to have - in addition to the two static options `insert` and `do not insert` - some dynamic options that you would otherwise find for parentheses like "insert if wrapped" and "insert if not empty".

Here's examples of what's currently possible (correct me if I'm wrong) and what I would like:

**Currently possible:**
```java
// either this:
// ----------

int[] myArray = {1, 2};
int[] myArray = {1, 2, 3, 4, 5, 6, 7,
8, 9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20};

method(new String[] {1, 2});

@Annotation(
attribute = {@NestedAnnotation(attr1 = "somevalue", attr2 = "somevalue"),
@NestedAnnotation(attr1 = "someothervalue", attr2 = "someothervalue")}
)

// or that:
// ----------

int[] myArray = {
1, 2
};
int[] myArray = {
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20
};

method(new String[] {
1, 2
});

@Annotation(attribute = {
@NestedAnnotation(attr1 = "somevalue", attr2 = "somevalue"),
@NestedAnnotation(attr1 = "someothervalue", attr2 = "someothervalue")
})
```

**What I would like:**
```java
// keep short array initializers on one line:
int[] myArray = {1, 2};
// especially as they might be used inline:
method(new String[] {1, 2});

// wrap longer array initializers like this:
int[] myArray = {
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
12, 13, 14, 15, 16, 17, 18, 19, 20
};

@Annotation(attribute = {
@NestedAnnotation(attr1 = "somevalue", attr2 = "somevalue"),
@NestedAnnotation(attr1 = "someothervalue", attr2 = "someothervalue")
})

// bonus points for this intermediary state:
int[] myArray =
{1, 2, 3, 4, 5, 6, 7, 8, 9};
```

Start by locating the formatter settings and logic for array-initializer braces, then compare them with the existing parenthesis options for wrapped and non-empty constructs. The work is done when array initializers support the requested dynamic newline behavior and the short, wrapped, nested-annotation, and bonus examples format as shown.

Written by the indexing model from the issue text.