Remove local strings from timing

[simonrozsival]

Summary

Remove the shared fast-timing implementation's local-string dependencies without introducing limits based on their former inline-storage thresholds.

Changes

• keep fixed arrays only for genuinely bounded Android properties, logcat messages, and integer formatting
• make assembly timing metadata formatting return the negative required capacity and retry with exact-size malloc() storage
• use the shared stack-first path helper for timing output
• reject a missing or empty TMPDIR and close the output file on setup failure
• remove the timing implementation's direct strings.hh dependency
• update the affected CoreCLR APK size references from Azure DevOps build 1566719

Validation

• Local native builds intentionally skipped; relying on CI validation
• APK size references refreshed from Azure DevOps build 1566719

[Copilot]

Pull request overview

This PR refactors the shared native fast-timing implementation to stop using dynamic_local_string for formatting and option parsing, moving toward fixed-buffer (char[]) handling to reduce reliance on the local-string hierarchy and eventually C++ runtime dependencies in shared native code.

Changes:

• Switch timing option retrieval/parsing (debug.mono.timing) to fixed buffers and in-place C-string tokenization.
• Replace timing log/event message construction with fixed char arrays and snprintf, returning event descriptions as string literals.
• Add AndroidSystem::monodroid_get_system_property overloads that write directly into caller-provided char[] buffers (MonoVM and CLR variants).

Show a summary per file

File	Description
src/native/mono/runtime-base/android-system.hh	Adds char[] overload for system property retrieval on the MonoVM side.
src/native/common/runtime-base/timing-internal.cc	Migrates timing option parsing, log message formatting, and output path building to fixed buffers.
src/native/common/include/runtime-base/timing-internal.hh	Updates timing message formatting helpers to use fixed buffers and snprintf.
src/native/clr/include/runtime-base/android-system.hh	Adds char[] overload for system property retrieval on the CLR side.

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 2
• Review effort level: Lite