[C++][Gandiva] Casting Float.POSITIVE_INFINITY/ Float.NEGATIVE_INFINITY/ Float.NaN to a decimal results in 0.0 instead of NULL

**Reporter**: [Kambham Vivek Shankar](https://issues.apache.org/jira/browse/ARROW-11867)
**Assignee**: [Quang Hoang](https://issues.apache.org/jira/browse/ARROW-11867) / @quanghgx

_{**Note**: *This issue was originally created as [ARROW-11867](https://issues.apache.org/jira/browse/ARROW-11867). Please see the [migration documentation](https://github.com/apache/arrow/issues/14542) for further details.*}

Begin by locating the C++ Gandiva path that casts floating-point values to decimals; the issue names no file or test. Done means Float.POSITIVE_INFINITY, Float.NEGATIVE_INFINITY, and Float.NaN cast to decimal produce NULL rather than 0.0.

Written by the indexing model from the issue text.