[native] Delete the std::format logging machinery from the CoreCLR host

[simonrozsival]

Part of #12533. Stacked on top of #12534.

Why

#12534 converted every CoreCLR-lane logging call site to the printf-style log_*f functions. That leaves the std::format-based macros and templates in clr/include/shared/log_types.hh with zero users.

They generated no code — the templates were never instantiated, which is why #12534 already showed the std::format fingerprint disappearing from every object file. But they kept <format> and the whole std::format API reachable from every CoreCLR translation unit, so it was one careless log_debug (LOG_X, "{}", x) away from coming back.

What

• Deletes the std::format macros and templates from clr/include/shared/log_types.hh. The file is now byte-for-byte identical to the existing NativeAOT stub.
• The one piece worth keeping was the std::string_view overload of log_write (used by common/runtime-base/timing-internal.cc). It was duplicated in both the CoreCLR and MonoVM copies of log_types.hh; it now lives once in common/include/shared/log_functions.hh, shared by all three lanes, and the MonoVM duplicate is removed.

No size change — and that's expected

	before	after
undefined libc++ refs (arm64 Release archive)	76	76

This removes dead declarations, not dead code. The win is that std::format can no longer be reintroduced into the CoreCLR host by accident, not fewer bytes.

Result

std::format is now completely absent from the clr/, common/ and nativeaot/ trees:

lane	std::format	#include <format>
clr/	0	0
common/ (shared)	0	0
nativeaot/	0	0
mono/	45	2

Only MonoVM still uses it — that's the remaining work on #12533.

Verification

Built the CoreCLR, MonoVM and NativeAOT lanes for arm64-v8a Release. All clean.

[Copilot]

Pull request overview

Removes the (now-unused) std::format-based logging wrappers from the CoreCLR host lane to keep <format> and the std::format API from being accidentally reintroduced via header usage, while deduplicating a small helper overload shared across runtime lanes.

Changes:

• Deletes std::format logging macros/templates from src/native/clr/include/shared/log_types.hh, leaving a minimal stub that routes through shared logging functions.
• Moves the log_write(LogCategories, LogLevel, std::string_view) convenience overload into common/include/shared/log_functions.hh and removes the duplicated MonoVM copy.
• Keeps lane-specific log_types.hh focused on lane behavior, with common helpers centralized.

Show a summary per file

File	Description
src/native/mono/shared/log_types.hh	Removes the duplicated std::string_view log_write overload now centralized in common shared logging helpers.
src/native/common/include/shared/log_functions.hh	Adds <string_view> include and centralizes the log_write convenience overload for shared use across lanes.
src/native/clr/include/shared/log_types.hh	Deletes the std::format macro/template machinery and reduces the header to a minimal stub including shared logging functions.

Review details

• Files reviewed: 3/3 changed files
• Comments generated: 1
• Review effort level: Lite

[simonrozsival]

Folded into #12534 — the change is small and inseparable from the call-site conversion it depends on, so it doesn't warrant a separate review pass.