Only consider the default-compile execution when update JDT settings

While in maven we can have many executions with many different settings,
JDT only supports one set of settings. If there are multiple with
conflicting settings currently "last win". This is especially bad when
using multi-release configuration where it leads to the last execution
overwrite the projects actual compile level.

This now checks through the ececutions and only use the default-compile
one to actually set up the project settings for JDT.

Author: laeubi

org.eclipse.m2e.jdt/src/org/eclipse/m2e/jdt/internal/AbstractJavaProjectConfigurator.java

@@ -638,6 +638,11 @@ protected void addJavaProjectOptions(Map<String, String> options, ProjectConfigu
     boolean enablePreviewFeatures = false;
 
     for(MojoExecution execution : getCompilerMojoExecutions(request, monitor)) {
+      String id = execution.getExecutionId();
+      if(!"default-compile".equals(id)) {
+        //Maven can have many but JDT only supports one config!
+        continue;
+      }
       release = getCompilerLevel(request.mavenProject(), execution, "release", release, RELEASES, monitor);
       //XXX ignoring testRelease option, since JDT doesn't support main/test classpath separation - yet
       source = getCompilerLevel(request.mavenProject(), execution, "source", source, SOURCES, monitor); //$NON-NLS-1$