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GH-37608: [C++][Gandiva] TO_DATE function supports YYYY-MM and YYYY (#37609)

Added fix for case when pattern does not contain day part

### Rationale for this change

TO_DATE Gandiva function returns wrong result if used with pattern 'YYYY-MM' or 'YYYY'.

### What changes are included in this PR?

Add a fix for case when tm_mday is zero to set it to 1

### Are these changes tested?

Added tests that cover described cases

### Are there any user-facing changes?

No

* Closes: #37608

Authored-by: DenisTarasyuk <131180287+DenisTarasyuk@users.noreply.github.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>