wrap-java: qualify Optional convenience method calls with self - #8

Problem

Optional convenience methods generated by wrap-java invoke the original method without a receiver. A parameter can therefore shadow that method and make the generated Swift fail to compile.

For example, this Java declaration:

public OptionalLong arg0(OptionalLong value) { return value; }

produces a Swift convenience method whose argument is also named arg0:

open func arg0Optional(_ arg0: Int64?) -> Int64? {
  Optional(javaOptional: arg0(arg0.toJavaOptional()))
}

The body attempts to call the Optional argument as a function. With this change, it explicitly calls the original method:

open func arg0Optional(_ arg0: Int64?) -> Int64? {
  Optional(javaOptional: self.arg0(arg0.toJavaOptional()))
}

Changes

• Qualify calls from Optional convenience methods with self.
• Preserve argument conversion, result conversion, and checked-exception handling.
• Add a regression using compiled Java source that covers instance and static methods, checked exceptions, Optional results, and methods whose only Optional value is an argument.

Validation

• Confirmed the new regression fails against the unmodified generator and passes with this change.
• swift test --disable-experimental-prebuilts --disable-sandbox: full Swift test suite passed.
• swift-format and git diff --check passed.

Tested with Apple Swift 6.4 and JetBrains Runtime 25 on macOS.