run Windows GitHub CI workflow on self-hosted runners

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from #23042)

(cherry picked from commit ce42b72)

.github/workflows/windows.yml

@@ -25,7 +25,7 @@ jobs:
             config: enable-fips
           - arch: win32
             config: --strict-warnings no-fips
-    runs-on: ${{matrix.os}}
+    runs-on: ${{ github.server_url == 'https://github.com' && matrix.os || format('{0}-self-hosted', matrix.os) }}
     steps:
     - uses: actions/checkout@v4
     - name: checkout fuzz/corpora submodule
@@ -75,7 +75,7 @@ jobs:
         os:
           - windows-2019
           - windows-2022
-    runs-on: ${{matrix.os}}
+    runs-on: ${{ github.server_url == 'https://github.com' && matrix.os || format('{0}-self-hosted', matrix.os) }}
     steps:
     - uses: actions/checkout@v4
     - name: checkout fuzz/corpora submodule
@@ -113,7 +113,7 @@ jobs:
         os:
           - windows-2019
           - windows-2022
-    runs-on: ${{matrix.os}}
+    runs-on: ${{ github.server_url == 'https://github.com' && matrix.os || format('{0}-self-hosted', matrix.os) }}
     steps:
     - uses: actions/checkout@v4
     - name: checkout fuzz/corpora submodule
@@ -159,7 +159,7 @@ jobs:
 # are we really learning sth new from win32? So let's save some CO2 for now disabling this
 #          - arch: win32
 #            config: -DCMAKE_C_COMPILER=gcc --strict-warnings no-fips
-    runs-on: ${{matrix.os}}
+    runs-on: ${{ github.server_url == 'https://github.com' && matrix.os || format('{0}-self-hosted', matrix.os) }}
     env:
       CYGWIN_NOWINPATH: 1
       SHELLOPTS: igncr