fix(function): reject out-of-range power results

[ck89119]

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

Fixes #25308

What this PR does / why we need it:

Reject non-finite results from POW and POWER with an out-of-range error instead of returning NaN or infinity.

The root cause was that the shared Power implementation appended the result of Go's math.Pow without checking for NaN or infinity. The implementation now returns ErrOutOfRange for non-finite results while preserving finite values and NULL handling.

Regression coverage includes negative bases with fractional exponents, zero raised to a negative exponent, mixed valid/invalid vectors, and distributed SQL cases for both aliases.

Validation:

• go test -count=1 -timeout 120s ./pkg/sql/plan/function
• go test -race -count=1 -timeout 120s -run '^TestPower(OutOfRange)?$' ./pkg/sql/plan/function
• go vet ./pkg/sql/plan/function
• go build ./pkg/sql/plan/function
• mo-tester: 53/53 statements passed for func_math_power.test

[qodo-code-review]

Qodo reviews are paused for this user.

Troubleshooting steps vary by plan Learn more →

On a Teams plan?
Reviews resume once this user has a paid seat and their Git account is linked in Qodo.
Link Git account →

Using GitHub Enterprise Server, GitLab Self-Managed, or Bitbucket Data Center?
These require an Enterprise plan - Contact us
Contact us →

[XuPeng-SH]

I did not find a blocker in this fix.

The change now rejects non-finite POW/POWER results as out-of-range while preserving normal finite values, NULL propagation, and alias behavior. The added select-list guard also matches the existing FunctionSelectList semantics, so filtered rows no longer evaluate the invalid branch.