Fix JavaList.Remove() always-false guard condition (&& -> ||)

[jonathanpeppers]

Problem

JavaList.Remove(object?) had an always-false guard condition at line 395:

if (i < 0 && i >= Count)
    return;
RemoveAt (i);

A value cannot simultaneously be < 0 and >= Count (Count is always non-negative), so this guard could never fire. The practical consequence: when IndexOf returns -1 (item not found), the dead guard passes and RemoveAt(-1) is called, throwing an exception instead of silently no-op-ing as the IList.Remove contract requires.

Fix

Change && to ||:

if (i < 0 || i >= Count)
    return;
RemoveAt (i);

This correctly returns early when:

• IndexOf returns -1 (item not in list) — the i < 0 branch
• A race condition shrinks the list between IndexOf and RemoveAt — the i >= Count branch

Changes

• src/Mono.Android/Android.Runtime/JavaList.cs: one-character fix (&& → ||)
• tests/Mono.Android-Tests/Mono.Android-Tests/Java.Interop/JavaListTest.cs: added RemoveNonExistentItemDoesNotThrow test — adds "foo", calls Remove("bar"), asserts no exception is thrown and count remains 1

[Copilot]

Pull request overview

Fixes JavaList.Remove(object?) to correctly no-op (per IList.Remove contract) when the item is not found, avoiding an out-of-range removal call.

Changes:

• Corrected an always-false guard condition in JavaList.Remove (&& → ||) to prevent RemoveAt(-1).
• Added an NUnit regression test verifying that removing a non-existent item does not throw and does not change the list count.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/Mono.Android/Android.Runtime/JavaList.cs	Fixes the guard in Remove(object?) so out-of-range indexes are safely ignored.
tests/Mono.Android-Tests/Mono.Android-Tests/Java.Interop/JavaListTest.cs	Adds regression coverage to ensure Remove is a no-op when the item is absent.