[llvm] [llvm] Use *Map::try_emplace (NFC) (PR #140843)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `llvm-nvptx-nvidia-ubuntu` running on `as-builder-7` while building `llvm` at step 2 "checkout".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/180/builds/17940

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 2 (checkout) failure: update (failure)
git version 2.43.0
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': Failed to connect to github.com port 443 after 135558 ms: Couldn't connect to server
fatal: unable to access 'https://github.com/llvm/llvm-project.git/': Failed to connect to github.com port 443 after 134997 ms: Couldn't connect to server

```

</details>

https://github.com/llvm/llvm-project/pull/140843