Fix NPE in Constructor predicate

This commit fixes a NullPointerException issue in the constructor hint
predicate. Prior to this commit, a hint for a constructor was directly
looked up and dereferenced a type hint without checking if there was one
first.

spring-core/src/test/java/org/springframework/aot/hint/ReflectionHintsPredicatesTests.java

@@ -136,6 +136,11 @@ class ReflectionHintsPredicatesTests {
 	@Nested
 	class ReflectionOnConstructor {
 
+		@Test
+		void constructorIntrospectionDoesNotMatchMissingHint() {
+			assertPredicateDoesNotMatch(reflection.onConstructor(publicConstructor).introspect());
+		}
+
 		@Test
 		void constructorIntrospectionMatchesConstructorHint() {
 			runtimeHints.reflection().registerType(SampleClass.class, typeHint -> typeHint.withConstructor(Collections.emptyList(), constructorHint -> {