Replace raw RuntimeException on reactor cycle with ProjectBuildingException.

When a reactor dependency cycle is detected, wrap the underlying
org.codehaus.plexus.util.dag.CycleDetectedException in a new
ProjectCycleException and throw a checked ProjectBuildingException
(as declared by ProjectBuilder) instead of a raw RuntimeException.

Keep non-cycle model problems on the existing ProjectBuildingException(results) path.

Author: arturobernalg

impl/maven-core/src/main/java/org/apache/maven/project/DefaultProjectBuilder.java

@@ -492,10 +492,22 @@ List<ProjectBuildingResult> build(List<File> pomFiles, boolean recursive) throws
                         .findAny()
                         .orElse(null);
                 if (cycle != null) {
-                    throw new RuntimeException(new ProjectCycleException(
+                    final CycleDetectedException cde = (CycleDetectedException) cycle.getException();
+
+                    final ProjectCycleException pce = new ProjectCycleException(
+                            "The projects in the reactor contain a cyclic reference: " + cycle.getMessage(), cde);
+
+                    // If you can resolve these from the problem/result, set them; otherwise leave null.
+                    final String projectId = null;
+                    final File pomFile = null;
+
+                    throw new ProjectBuildingException(
+                            projectId,
                             "The projects in the reactor contain a cyclic reference: " + cycle.getMessage(),
-                            (CycleDetectedException) cycle.getException()));
+                            pomFile,
+                            pce);
                 }
+
                 throw new ProjectBuildingException(results);
             }