[MINOR][ML] Array.fill(0) -> Array.ofDim; Array.empty[Int] -> Array.emptyIntArray

[zhengruifeng]

What changes were proposed in this pull request?

1, for primitive types Array.fill(n)(0) -> Array.ofDim(n);
2, for AnyRef types Array.fill(n)(null) -> Array.ofDim(n);
3, for primitive types Array.empty[XXX] -> Array.emptyXXXArray

Why are the changes needed?

Array.ofDim avoid assignments;
Array.emptyXXXArray avoid create new object;

Does this PR introduce any user-facing change?

No

How was this patch tested?

existing testsuites

[SparkQA]

Test build #116290 has finished for PR 27133 at commit aa9240f.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

Looks good if tests pass

[SparkQA]

Test build #116298 has finished for PR 27133 at commit 873dce0.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[HyukjinKwon]

Merged to master.

[zhengruifeng]

@HyukjinKwon Thanks for reviewing!