Use a dedicated job for the native build

azure-pipelines.yml

@@ -87,9 +87,6 @@ stages:
               options: '-B --settings azure-mvn-settings.xml -DskipTests=true -Dno-format'
 
   #This stage builds the Quarkus artifacts needed for native image testing
-  #but also tests JDK8 linux. While it would be more parallel to have a separate JDK8 test run,
-  #and build this run with tests skipped, this means that if there is a problem with the JVM run
-  #we do not waste time on native runs, and also uses less agent time overall
   - stage: build_artifact_for_native_stage
     displayName: 'Build for Native'
     dependsOn: cache_maven_repo_stage
@@ -104,8 +101,19 @@ stages:
           imageName: 'quarkus:$(build.buildId)'
 
         steps:
-          - template: ci-templates/jvm-build-steps.yaml
+          - task: CacheBeta@0 #we know the very first job will have restored or created this, so this will never write built artifacts to the cache
+            inputs:
+              key: maven | bom/runtime/pom.xml
+              path: $(Pipeline.Workspace)/.m2/repository/
+              securityNamespace: cache
+            displayName: Restore Maven Cache
 
+          - task: Maven@3
+            displayName: 'Maven Build'
+            inputs:
+              goals: 'install'
+              mavenOptions: $(MAVEN_OPTS)
+              options: '-DskipTests -Dno-format'
           - publish: $(MAVEN_CACHE_FOLDER)
             artifact: BuiltMavenRepo
 
@@ -113,6 +121,17 @@ stages:
     displayName: 'Run JVM Tests'
     dependsOn: cache_maven_repo_stage
     jobs:
+
+      - job: Build_JDK8_Linux
+        displayName: 'Build JDK8 Linux'
+        timeoutInMinutes: 60
+        pool:
+          vmImage: 'Ubuntu 16.04'
+        variables:
+          imageName: 'quarkus:$(build.buildId)'
+        steps:
+          - template: ci-templates/jvm-build-steps.yaml
+
       - job: Windows_Build
         displayName: 'Windows JVM Build'
         timeoutInMinutes: 60