RFR: 8341272: Factory to create wide iinc instruction with small arguments

[Trevor Bond]

On Tue, 9 Dec 2025 20:59:58 GMT, Trevor Bond <duke at openjdk.org> wrote:

> Add a new factory method to `IncrementInstruction` that allows the explicit creation of a wide iinc instruction, even with a `slot` and `constant` that could fit into a normal iinc instruction. Previously, only one factory for iinc instructions existed, which inferred the type of instruction needed given the size of `slot` and `constant`. Add additional test cases for the new factory as well. All tier 1 tests and classfile tests have passed with these changes.

Thank you for your comments and review. I have made some changes that should address those.

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PR Comment: https://git.openjdk.org/jdk/pull/28729#issuecomment-3634977206