[Build] Replace use of coactions/setup-xvfb in shared GH workflows

Author: HannesWell

.github/workflows/codeQLworkflow.yml

@@ -90,9 +90,8 @@ jobs:
         tycho-version: 4.0.12
 
     - name: Build with Maven
-      uses: coactions/setup-xvfb@6b00cf1889f4e1d5a48635647013c0508128ee1a
-      with:
-       run: >- 
+      run: >-
+        ${{ runner.os == 'Linux' && 'xvfb-run' || '' }}
         mvn --batch-mode --no-transfer-progress --show-version --update-snapshots --errors
         ${{ inputs.without-EF-infra && '-Dtycho.version=4.0.12' || '' }}
         -Dcompare-version-with-baselines.skip=true

.github/workflows/mavenBuild.yml

@@ -47,6 +47,10 @@ jobs:
           - { name: Linux,   os: ubuntu-latest  }
           - { name: Windows, os: windows-latest }
           - { name: MacOS,   os: macos-13   }
+    defaults:
+      run: # Run always on bash, because powershell (the Windows default) interprets dots in arguments differently
+        shell: bash
+
     name: Verify ${{ matrix.config.name }}
     steps:
     - name: Checkout
@@ -88,9 +92,8 @@ jobs:
         target: .github/matcher
     - run: echo "::add-matcher::.github/matcher/${{ steps.api-tools-matcher.outputs.filename }}"
     - name: Build with Maven
-      uses: coactions/setup-xvfb@6b00cf1889f4e1d5a48635647013c0508128ee1a
-      with:
-       run: >- 
+      run: >-
+        ${{ runner.os == 'Linux' && 'xvfb-run' || '' }}
         mvn --batch-mode --no-transfer-progress --show-version --update-snapshots --errors
         ${{ inputs.without-EF-infra && '-Dtycho.version=4.0.12' || '' }}
         -Dcompare-version-with-baselines.skip=false