Ensure all files end with a newline

Update all files to ensure that they always end with a new line.

Issue: SPR-16968

spring-core/src/main/java/org/springframework/asm/Context.java

@@ -142,4 +142,4 @@ class Context {
      * The stack values of the latest stack map frame that has been parsed.
      */
     Object[] stack;
-}
+}

spring-core/src/main/java/org/springframework/core/annotation/package-info.java

@@ -7,4 +7,4 @@
 package org.springframework.core.annotation;
 
 import org.springframework.lang.NonNullApi;
-import org.springframework.lang.NonNullFields;
+import org.springframework.lang.NonNullFields;