allocation-instrumenter breaks JPMS compliant builds

The allocation-instrumenter uses the shade plugin to include some guava classes into its jar. Any project - such as Log4j 2 - that includes this tool as a test dependency will fail to build if they have other dependencies that require guava and have a module-info.java in their jar. The errors all resemble

```
[ERROR] error: module com.lmax.disruptor reads package com.google.thirdparty.publicsuffix from both guava and java.allocation.instrumenter
[ERROR] error: module org.jctools.core reads package com.google.thirdparty.publicsuffix from both guava and java.allocation.instrumenter
[ERROR] error: module org.yaml.snakeyaml reads package com.google.thirdparty.publicsuffix from both guava and java.allocation.instrumenter
```