Account for https://issues.apache.org/jira/browse/GROOVY-9736 (#1748)

Author: paulk-asert

build.gradle

@@ -37,6 +37,7 @@ apply plugin: 'project-report'
 
 allprojects {
     repositories {
+        mavenCentral()
         maven { url "https://repo.grails.org/grails/core" }
         if(isSnapshot) {
             maven { url "https://repo.grails.org/grails/libs-snapshots-local" }

grails-datastore-gorm/src/main/groovy/org/grails/datastore/gorm/services/transform/ServiceTransformation.groovy

@@ -19,6 +19,7 @@ import grails.gorm.services.Service
 import grails.gorm.transactions.NotTransactional
 import groovy.transform.CompilationUnitAware
 import groovy.transform.CompileStatic
+import groovyjarjarasm.asm.Opcodes
 import org.codehaus.groovy.ast.AnnotationNode
 import org.codehaus.groovy.ast.ClassHelper
 import org.codehaus.groovy.ast.ClassNode
@@ -191,7 +192,7 @@ class ServiceTransformation extends AbstractTraitApplyingGormASTTransformation i
             ClassNode superClass = isInterface ? ClassHelper.OBJECT_TYPE : classNode.plainNodeReference
             String serviceClassName = classNode.nameWithoutPackage
             ClassNode impl = new ClassNode("${packageName}\$${serviceClassName}Implementation", // class name
-                    ACC_PUBLIC, // public
+                    Opcodes.ACC_PUBLIC, // public
                     superClass,
                     interfaces)