profiling: --collapsed export fails with UnicodeEncodeError on non-ASCII frame names

Bug report

Bug description:

CollapsedStackCollector.export (Lib/profiling/sampling/stack_collector.py) opens its output with open(filename, "w") — no encoding=. It is the only exporter in that module missing it; FlamegraphCollector.export, the JSONL exporter and the heatmap exporter all pass encoding="utf-8". Because the collapsed format writes frame names verbatim (the JSON exporters escape non-ASCII via ensure_ascii), --collapsed export raises UnicodeEncodeError when a sampled frame's function or file name contains non-ASCII characters under a non-UTF-8 locale, or surrogate-escaped characters (from an undecodable path) on any locale:

UnicodeEncodeError: 'ascii' codec can't encode characters ...
UnicodeEncodeError: 'utf-8' codec can't encode character '\udc80' ... surrogates not allowed

Non-English identifiers are common and non-UTF-8 locales are supported, so profiling such a program with --collapsed produces no output and an uncaught error.

CPython versions tested on:

CPython main

Operating systems tested on:

Linux, macOS

Linked PRs

• gh-156811
• gh-156814

Comience con Lib/profiling/sampling/stack_collector.py y compare CollapsedStackCollector.export con los demás exportadores que especifican una salida UTF-8. Compruebe primero los PR enlazados gh-156811 y gh-156814; se considera terminado cuando la exportación collapsed funciona correctamente para nombres de frame no ASCII y nombres de frame escapados con surrogates, sin producir UnicodeEncodeError.