Fix [serial] compiler warnings

Fix serialization warnings by applying @SuppressWarnings("serial")
when appropriate.

In certain cases and for unknown reasons, a correctly-placed
@SuppressWarnings("serial") annotation will fix the warning at the
javac level (i.e. the Gradle command-line), but will produce an
"unnecessary @SuppressWarnings" warning within Eclipse. In these
cases, a private static final serialVersionUID field has been added
with the default value of 1L.

spring-aop/src/test/java/org/springframework/aop/aspectj/TrickyAspectJPointcutExpressionTests.java

@@ -115,6 +115,7 @@ public class TrickyAspectJPointcutExpressionTests {
 
 	}
 
+	@SuppressWarnings("serial")
 	public static class TestException extends RuntimeException {
 
 		public TestException(String string) {

spring-aop/src/test/java/org/springframework/aop/target/LazyInitTargetSourceTests.java

@@ -80,6 +80,7 @@ public final class LazyInitTargetSourceTests {
 	}
 
 
+	@SuppressWarnings("serial")
 	public static class CustomLazyInitTargetSource extends LazyInitTargetSource {
 
 		protected void postProcessTargetObject(Object targetObject) {

spring-aop/src/test/java/org/springframework/aop/target/PrototypeBasedTargetSourceTests.java

@@ -62,6 +62,8 @@ public final class PrototypeBasedTargetSourceTests {
 
 	private static class TestTargetSource extends AbstractPrototypeBasedTargetSource {
 
+		private static final long serialVersionUID = 1L;
+
 		/**
 		 * Nonserializable test field to check that subclass
 		 * state can't prevent serialization from working
@@ -77,4 +79,4 @@ public final class PrototypeBasedTargetSourceTests {
 		}
 	}
 
-}
+}