gitlab-ci: terminate all msys2 related processes before Windows/Aarch…

…64 jobs.

This is the command suggest by MSYS2 developers here:
msys2/MSYS2-packages#4340 (comment)

They also say to run it outside the MSYS2 environment, which is why it's in the
CI rules, not in the shell script.

Honestly at this point, it feels like we are just stacking weird workaround to
get it to fail not too often. ;-(

.gitlab-ci.yml

@@ -688,6 +688,7 @@ deps-win-a64:
     - if ($stuck -eq "True") {
         Remove-Item -Force -Path "C:\msys64\var\lib\pacman\db.lck";
         Write-Output "Cleaned previous stuck pacman" }
+    - taskkill /F /FI "MODULES eq msys-2.0.dll"
     - Start-Job -ScriptBlock{sleep 90; taskkill /t /F /IM "pacman.exe"}
     - C:\msys64\usr\bin\bash -lc "bash -x ./build/windows/gitlab-ci/1_build-deps-msys2.sh"
   retry: 2
@@ -725,6 +726,7 @@ gimp-win-a64:
     # Temporary patch until we use the latest LLVM.
     - git apply ./build/windows/patches/0001-clang-rc-files-fix.patch
     - git apply ./build/windows/patches/0004-clang-windres.patch
+    - taskkill /F /FI "MODULES eq msys-2.0.dll"
     - Start-Job -ScriptBlock{sleep 90; taskkill /t /F /IM "pacman.exe"}
     - C:\msys64\usr\bin\bash -lc "bash -x ./build/windows/gitlab-ci/2_build-gimp-msys2.sh"
   retry: 2
@@ -762,6 +764,7 @@ packaging-win-a64:
     - if ($stuck -eq "True") {
         Remove-Item -Force -Path "C:\msys64\var\lib\pacman\db.lck";
         Write-Output "Cleaned previous stuck pacman" }
+    - taskkill /F /FI "MODULES eq msys-2.0.dll"
     - Start-Job -ScriptBlock{sleep 90; taskkill /t /F /IM "pacman.exe"}
     - C:\msys64\usr\bin\bash -lc "bash -x ./build/windows/gitlab-ci/3_package-gimp-uni_base.sh"
     - cd gimp-a64