Build LLVM for Windows (#248)

This PR changes the CI build scripts to also build LLVM for windows.
**It doesn't build `revive` itself for windows**. This will come in a
follow up. But once we have a LLVM binary release the turn around time
will be much quicker for experimenting with the revive windows build.

I manually uploaded the release those changes produce
[here](https://github.com/paritytech/revive-alex-workflowtest/releases/tag/llvm-18.1.8-revive.22f3ceb).
This enables this PR's CI to find the proper release. This is necessary
because I am also making changes to the folder structure and artifact
naming that the other CI jobs are depending on.

Releases generated from this branch can be inspected here:
https://github.com/paritytech/revive-alex-workflowtest/releases/tag/v0.1.0-dev.12

Summary of changes:
- Change `llvm-builder` to use MSVC toolchain on windows
- Fix `llvm-builder` to work with `.exe` files
- Unify the llvm release jobs into a single one. This removed a lot of
copy pasted code and also speeds up the build by giving each their own
runner.
- Use the LLVM target triple to name the binary releases instead of an
ad-hoc naming convention
- Remove the nested folder hierarchy inside the llvm release. Its just
now a single folder `llvm-<target>` that contains the toolchain.
- Give jobs and workflows consistent names
- Replace all runners bei their `*-latest` counterpart
- Only use `parity-large` to build llvm now. All other jobs use github
runners

crates/llvm-builder/src/platforms/shared.rs

@@ -8,7 +8,7 @@ use std::path::Path;
 use std::process::Command;
 
 /// The build options shared by all platforms.
-pub const SHARED_BUILD_OPTS: [&str; 19] = [
+pub const SHARED_BUILD_OPTS: [&str; 21] = [
     "-DPACKAGE_VENDOR='Parity Technologies'",
     "-DCMAKE_BUILD_WITH_INSTALL_RPATH=1",
     "-DLLVM_BUILD_DOCS='Off'",
@@ -28,6 +28,8 @@ pub const SHARED_BUILD_OPTS: [&str; 19] = [
     "-DCMAKE_EXPORT_COMPILE_COMMANDS='On'",
     "-DPython3_FIND_REGISTRY='LAST'", // Use Python version from $PATH, not from registry
     "-DBUG_REPORT_URL='https://github.com/paritytech/contract-issues/issues/'",
+    "-DCLANG_ENABLE_ARCMT='Off'",
+    "-DCLANG_ENABLE_STATIC_ANALYZER='Off'",
 ];
 
 /// The build options shared by all platforms except MUSL.