Missing assembly code in the assembly view

This issue is similar to #3741, but for the assembly view.

Once the initial version of the assembly view lands, the assembly view will only be able to show assembly code in a small number of cases. Over time, we should add support for more cases.

This issue tracks the implementation status of the various cases.

* Before uploading / sharing, in profiles captured within Firefox:
* [x] Assembly code for native code (C/C++/Rust)
* [ ] Assembly code for JIT functions
* [ ] Assembly code for the Baseline Interpreter
* [ ] Assembly code for Baseline-compiled JavaScript functions
* [ ] Assembly code for Ion-compiled JavaScript functions
* [ ] Assembly code for ICs
* [ ] Assembly code for various trampolines
* [ ] Assembly code for jitted regular expressions
* Before uploading / sharing, in profiles captured with `samply`:
* [x] Assembly code for native code (C/C++/Rust)
* After uploading / sharing:
* [ ] Assembly code for official Firefox binaries on Windows
* [ ] Assembly code for official Firefox binaries on macOS / Linux / Android
* [ ] Assembly code which is embedded into and uploaded together with the profile

┆Issue is synchronized with this [Jira Task](https://mozilla-hub.atlassian.net/browse/FP-619)