[iOS] Implement IgnoreSymbols for CompreInfo in managed code

[matouskozak]

Supersedes #118523.

Implementation of CompareOptions.IgnoreSymbols for IndexOf, IsPrefix, IsSuffix, Compare on iOS. Because ObjectiveC string APIs (https://developer.apple.com/documentation/foundation/nsstring/compareoptions?language=objc) don't provide a direct alternative to IgnoreSymbols option, we filter the symbols from the strings in the managed code and after returning from native, we re-calculate the original index and length.

The implementation works in a following:

1. Preprocess the source and search strings by removing the symbols.
2. Invoke the native API for comparison.
3. Map the range from preprocessed source string back to the original string to get the index and length.

---

Fixes #111895

[matouskozak]

/azp run runtime-extra-platforms

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[tarekgh]

/azp run runtime-ioslike

[azure-pipelines]

Azure Pipelines could not run because the pipeline triggers exclude this branch/path.

[Copilot]

Pull Request Overview

This PR implements support for the CompareOptions.IgnoreSymbols option in CompareInfo operations on iOS using hybrid globalization. Previously, this option was not supported on Apple platforms and would throw exceptions.

• Adds native implementation for symbol filtering in managed code for iOS
• Updates test cases to enable IgnoreSymbols tests on Apple platforms
• Modifies native enum definition to use explicit types and hex values

Reviewed Changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

File	Description
src/native/libs/System.Globalization.Native/pal_collation.m	Updates enum definition to use explicit int32_t type and hex values
src/libraries/System.Runtime/tests/System.Globalization.Tests/CompareInfo/*.cs	Removes platform-specific test exclusions and adds comprehensive IgnoreSymbols test cases
src/libraries/System.Private.CoreLib/src/System/Globalization/CompareInfo.iOS.cs	Implements IgnoreSymbols functionality with symbol filtering buffer and character categorization
src/libraries/System.Private.CoreLib/src/System/Globalization/CompareInfo.Icu.cs	Updates method signatures to use ReadOnlySpan parameters instead of raw pointers

[matouskozak]

/azp run runtime-maccatalyst,runtime-ioslikesimulator

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[matouskozak]

/azp run runtime-maccatalyst

[azure-pipelines]

No pipelines are associated with this pull request.

[matouskozak]

/azp run runtime-maccatalyst

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[matouskozak]

/azp run runtime-ioslike

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[matouskozak]

The failures on Apple mobile are unrelated to this PR and are already known.

[tarekgh]

Added one comment/question. LGTM otherwise.