Remove JDK 9 and JDK 10 build from Jenkins pipeline

Closes gh-8482

Author: eleftherias

Jenkinsfile

@@ -99,50 +99,6 @@ try {
 			}
 		}
 	},
-	jdk9: {
-		stage('JDK 9') {
-			node {
-				checkout scm
-				sh "git clean -dfx"
-				try {
-					withCredentials([GRADLE_ENTERPRISE_CACHE_USER,
-						 GRADLE_ENTERPRISE_SECRET_ACCESS_KEY]) {
-						withEnv([jdkEnv("jdk9"),
-							 "GRADLE_ENTERPRISE_CACHE_USERNAME=${GRADLE_ENTERPRISE_CACHE_USERNAME}",
-							 "GRADLE_ENTERPRISE_CACHE_PASSWORD=${GRADLE_ENTERPRISE_CACHE_PASSWORD}",
-							 "GRADLE_ENTERPRISE_ACCESS_KEY=${GRADLE_ENTERPRISE_ACCESS_KEY}"]) {
-							sh "./gradlew test --stacktrace"
-						}
-					}
-				} catch(Exception e) {
-					currentBuild.result = 'FAILED: jdk9'
-					throw e
-				}
-			}
-		}
-	},
-	jdk10: {
-		stage('JDK 10') {
-			node {
-				checkout scm
-				sh "git clean -dfx"
-				try {
-					withCredentials([GRADLE_ENTERPRISE_CACHE_USER,
-						 GRADLE_ENTERPRISE_SECRET_ACCESS_KEY]) {
-						withEnv([jdkEnv("jdk10"),
-							 "GRADLE_ENTERPRISE_CACHE_USERNAME=${GRADLE_ENTERPRISE_CACHE_USERNAME}",
-							 "GRADLE_ENTERPRISE_CACHE_PASSWORD=${GRADLE_ENTERPRISE_CACHE_PASSWORD}",
-							 "GRADLE_ENTERPRISE_ACCESS_KEY=${GRADLE_ENTERPRISE_ACCESS_KEY}"]) {
-							sh "./gradlew test --stacktrace"
-						}
-					}
-				} catch(Exception e) {
-					currentBuild.result = 'FAILED: jdk10'
-					throw e
-				}
-			}
-		}
-	},
 	jdk11: {
 		stage('JDK 11') {
 			node {