fix array_repeat scalar path overflows total repeated-value count

[xiedeyantu]

Which issue does this PR close?

• Closes panic: array_repeat scalar path overflows total repeated-value count #22218

Rationale for this change

The scalar path of array_repeat can overflow while computing the total number of repeated values. Previously, the implementation used unchecked accumulation for these totals, which could lead to overflow behavior that was not explicitly handled. This change makes the capacity and offset calculations overflow-safe and returns a clear execution error when the total output size exceeds usize.

What changes are included in this PR?

• Adds overflow checks for the total repeated value count in the scalar array_repeat path.
• Adds overflow checks for outer and inner total size calculations in the list repeat path.
• Preserves the existing behavior where non-positive counts are treated as zero.
• Adds sqllogictest coverage for the overflow error case.

Are these changes tested?

• Yes. A new sqllogictest covers the scalar overflow failure case for array_repeat.
• Existing related tests continue to pass.

Are there any user-facing changes?

• Yes. For extremely large inputs, array_repeat now returns a clear execution error instead of relying on implicit overflow behavior.
• Normal inputs are unchanged.