Remove spring-asm and inline ASM 4 into spring-core

ASM 4.0 is generally compatibile with Java 7 classfiles, particularly
including 'invokedynamic' instructions. This is important when
considering that Spring's component-scanning support is internally
ASM-based and it is increasingly likely that component classes having
invokedynamic instructions may be encountered and read by ASM.
This upgrade, then, is primarily preventive in nature.

Changes include:

 - upgrade from ASM 2.2.3 to ASM 4.0

 - adapt to ASM API changes as necessary throughout spring-core,
   resulting in no impact to the public Spring API.

 - remove dedicated spring-asm module

 - use new :spring-core:asmRepackJar task to repackage
   org.objectweb.asm => org.springframework.asm as per usual and write
   repackaged classes directly into spring-core jar

The choice to eliminate the spring-asm module altogether and instead
inline the repackaged classes directly into spring-core is first to
eliminate an otherwise unnecessary second jar. spring-core has a
non-optional dependency on spring-asm meaning it is always on the
application classpath. This change simplifies that situation by
consoliding two jars into one. The second reason for this choice is in
anticipation of upgrading CGLIB to version 3 and inlining it into
spring-core as well. See subsequent commit for details.

Issue: SPR-9669

spring-asm/src/main/java/org/springframework/asm/SpringAsmInfo.java

@@ -1,31 +0,0 @@
-/*
- * Copyright 2002-2012 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.asm;
-
-/**
- * Placeholder to allow Javadoc generation. Required because
- * <a href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4492654">this bug</a>
- * does not allow the generation of Javadoc for packages having only a
- * {@code package-info.java} file.
- * <p>See <a href="package-summary.html">package-level Javadoc</a> for more
- * information on {@code org.springframework.asm}.
- *
- * @author Chris Beams
- * @since 3.2
- */
-public final class SpringAsmInfo {
-}

spring-asm/src/main/java/org/springframework/asm/package-info.java

@@ -1,11 +0,0 @@
-/**
- * Spring's repackaging of {@code org.objectweb.asm.*} (for internal use only).
- * <p>This repackaging technique avoids any potential conflicts with
- * dependencies on ASM at the application level or from other third-party
- * libraries and frameworks.
- * <p>As this repackaging happens at the classfile level, sources and Javadoc
- * are not available here. See the original ObjectWeb
- * <a href="http://asm.ow2.org/asm223/javadoc/user">ASM 2.2.3 Javadoc</a>
- * for details when working with these classes.
- */
-package org.springframework.asm;