Better support for split packages.

- if you force an inclusion via 'inclusions=foo..*' then
  allow for everything in that package to be made reloadable
  regardless of it coming from jar or disk.
- when inclusion patterns don't match fall back on regular
  acceptance mechanisms (like package cache, etc) rather
  than just dismissing it.
- the results of decision making around making things
  reloadable are now enums/objects rather than plain booleans
  so that later we can do further analysis on those
  decisions.

Issue: https://github.com/grails/grails-core/issues/8817

testdata/src/main/java/grails/plugins/A.java

@@ -0,0 +1,8 @@
+package grails.plugins;
+
+public class A {
+
+	public void foo() {
+		System.out.println("A.foo() running");
+	}
+}

testdata/src/main/java/grails/plugins/B.java

@@ -0,0 +1,8 @@
+package grails.plugins;
+
+public class B extends A {
+
+	public void foo() {
+		System.out.println("B.foo() running");
+	}
+}

testdata/src/main/java/grails/plugins/B2.java

@@ -0,0 +1,8 @@
+package grails.plugins;
+
+public class B2 extends A {
+
+	public void foo() {
+		System.out.println("B2.foo() running");
+	}
+}