Stop adding MSYS2 to PATH, take 2

[mati865]

An alternative to #149600

[mati865]

@bors try jobs=i686-pc-windows-gnu,aarch64-pc-windows-gnullvm

In the previous jobs logs we can see:

2025-12-01T17:45:46.4767273Z PATH=/mingw64/bin:/usr/bin:/c/Users/runneradmin/bin:/d/a/rust/rust/ninja:/d/a/rust/rust/mingw32/bin:/d/a/rust/rust/sccache:/c/Program Files/MongoDB/Server/7.0/bin:/c/vcpkg:/c/tools/zstd:/c/hostedtoolcache/windows/stack/3.7.1/x64:/c/cabal/bin:/c/ghcup/bin:/c/mingw64/bin:/c/Program Files/dotnet:/c/Program Files/MySQL/MySQL Server 8.0/bin:/c/Program Files/R/R-4.5.2/bin/x64:/c/SeleniumWebDrivers/GeckoDriver:/c/SeleniumWebDrivers/EdgeDriver:/c/SeleniumWebDrivers/ChromeDriver:/c/Program Files (x86)/sbt/bin:/c/Program Files (x86)/GitHub CLI:/bin:/c/Program Files (x86)/pipx_bin:/c/npm/prefix:/c/hostedtoolcache/windows/go/1.24.9/x64/bin:/c/hostedtoolcache/windows/Python/3.9.13/x64/Scripts:/c/hostedtoolcache/windows/Python/3.9.13/x64:/c/hostedtoolcache/windows/Ruby/3.3.10/x64/bin:/c/Program Files/OpenSSL/bin:/c/tools/kotlinc/bin:/c/hostedtoolcache/windows/Java_Temurin-Hotspot_jdk/17.0.17-10/x64/bin:/c/Program Files/ImageMagick-7.1.2-Q16-HDRI:/c/Program Files/Microsoft SDKs/Azure/CLI2/wbin:/c/ProgramData/kind:/c/ProgramData/Chocolatey/bin:/c/Windows/system32:/c/Windows:/c/Windows/System32/Wbem:/c/Windows/System32/WindowsPowerShell/v1.0:/c/Windows/System32/OpenSSH:/c/Program Files/PowerShell/7:/c/Program Files/Microsoft/Web Platform Installer:/c/Program Files/Microsoft SQL Server/Client SDK/ODBC/170/Tools/Binn:/c/Program Files/Microsoft SQL Server/150/Tools/Binn:/c/Program Files/dotnet:/c/Program Files (x86)/Windows Kits/10/Windows Performance Toolkit:/c/Program Files (x86)/WiX Toolset v3.14/bin:/c/Program Files/Microsoft SQL Server/130/DTS/Binn:/c/Program Files/Microsoft SQL Server/140/DTS/Binn:/c/Program Files/Microsoft SQL Server/150/DTS/Binn:/c/Program Files/Microsoft SQL Server/160/DTS/Binn:/c/Program Files/Microsoft SQL Server/170/DTS/Binn:/c/ProgramData/chocolatey/lib/pulumi/tools/Pulumi/bin:/c/Program Files/CMake/bin:/c/Strawberry/c/bin:/c/Strawberry/perl/site/bin:/c/Strawberry/perl/bin:/c/ProgramData/chocolatey/lib/maven/apache-maven-3.9.11/bin:/c/Program Files/Microsoft Service Fabric/bin/Fabric/Fabric.Code:/c/Program Files/Microsoft SDKs/Service Fabric/Tools/ServiceFabricLocalClusterManager:/c/Program Files/nodejs:/cmd:/mingw64/bin:/usr/bin:/c/Program Files/GitHub CLI:/c/tools/php:/c/Program Files (x86)/sbt/bin:/c/Program Files/Amazon/AWSCLIV2:/c/Program Files/Amazon/SessionManagerPlugin/bin:/c/Program Files/Amazon/AWSSAMCLI/bin:/c/Program Files/Microsoft SQL Server/130/Tools/Binn:/c/Program Files/mongosh:/c/Program Files/LLVM/bin:/c/Program Files (x86)/LLVM/bin:/c/Users/runneradmin/.dotnet/tools:/c/Users/runneradmin/.cargo/bin:/c/Users/runneradmin/AppData/Local/Microsoft/WindowsApps

So, this change likely won't help but let's see.

[rust-bors]

💔 Test for 2b11fdb failed: CI. Failed job:

• Calculate job matrix (web logs, extended logs)

[mati865]

@bors try jobs=dist-i686-mingw

[mati865]

@bors try cancel

GitHub is really annoying in how it handles adding to PATH. This won't work.

[rust-bors]

Try build cancelled. Cancelled workflows:

• https://github.com/rust-lang/rust/actions/runs/19902646914

[mati865]

@bors try jobs=dist-i686-mingw

[mati865]

@bors try cancel

[rust-bors]

Try build cancelled. Cancelled workflows:

• https://github.com/rust-lang/rust/actions/runs/19903577381

[mati865]

@bors try jobs=dist-i686-mingw

[rust-bors]

💔 Test for 56e2f27 failed: CI

[tgross35]

Is there a test we can add to check for #136795 somehow?

[mati865]

i686-pc-windows-gnu doesn't run tests on CI, so no idea.