Explicitly compute null count in concatenate APIs

[vyasr]

Description

The total number of nulls in the output can be computed by summing the nulls in the input columns.

Contributes to #11968

Checklist

• I am familiar with the Contributing Guidelines.
• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[vyasr]

@vuule locally this change passes all tests for concatenation itself but fails some tests in the Parquet reader. Would you be able to help me look into those? I am unsure if the reader is catching some edge cases that the test is missing, or if the Parquet code has some null sanitization bug that is causing the failures. I mention sanitization because the failure specifically occurs for list and struct types.

[vuule]

@vuule locally this change passes all tests for concatenation itself but fails some tests in the Parquet reader. Would you be able to help me look into those? I am unsure if the reader is catching some edge cases that the test is missing, or if the Parquet code has some null sanitization bug that is causing the failures. I mention sanitization because the failure specifically occurs for list and struct types.

@nvdbaranec

[vuule]

Tests fail because chunked Parquet reader returns columns with incorrect null count, and the new concatenate relies on this info.
Opened #13111 with a potential fix.

[vyasr]

Depends on #13111

[vyasr]

/merge