docc validation needs JAVA_HOME to be set up

Author: ktoso

.github/workflows/pull_request.yml

@@ -5,7 +5,26 @@ on:
     types: [opened, reopened, synchronize]
 
 jobs:
+  env-setup:
+    name: Setup CI Environment
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: true
+      matrix:
+        swift_version: ['6.1.2']
+        os_version: ['jammy']
+        jdk_vendor: ['corretto']
+    container:
+      image: ${{ (contains(matrix.swift_version, 'nightly') && 'swiftlang/swift') || 'swift' }}:${{ matrix.swift_version }}-${{ matrix.os_version }}
+    env:
+      SWIFT_JAVA_VERBOSE: true
+    steps:
+      - uses: actions/checkout@v4
+      - name: Prepare CI Environment
+        uses: ./.github/actions/prepare_env
+        
   soundness:
+    needs: env-setup
     uses: swiftlang/github-workflows/.github/workflows/soundness.yml@main
     with:
       # Not API stable package (yet)