GCC warnings don't go away until manual recompile

### Brief Issue Summary

I'm not sure if this is an issue with CMake Tools or cpptools, or if it's a bug at all, but GCC warnings reported by the CMake Tools output parser don't go away until I manually recompile through CMake Tools. The error reporting by cpptools works as I type, but it seems like that's just for hard syntax errors, not warnings.

### Expected:

1. Fix problem reported by GCC warning
2. Save file
3. Automatic recompile occurs, removing the squiggle and the entry in the problems pane

### Apparent Behavior:

1. Fix problem reported by GCC warning
2. Save file
3. Nothing happens
4. Run the "build target" action
5. Squiggle and warning goes away

### CMake Tools Log

There isn't any activity after saving a file, so I don't think there are relevant logs

### Platform and Versions

- **Operating System**: Windows host, RHEL7 remote SSH connection
- **CMake Version**: 3.17.5
- **VSCode Version**: 1.56.2
- **CMake Tools Extension Version**: 1.7.3
- **Compiler/Toolchain**: gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-44)

Reproduce the warning lifecycle using the reported Windows-to-RHEL7 remote setup and versions, focusing on the CMake Tools output parser and the save-triggered build flow. Compare saving the file with running the “build target” action; done means a fixed GCC warning disappears from both the squiggle and Problems pane without a manual build.

Written by the indexing model from the issue text.