Update JaCoCo Jenkins artifacts for Java 9 support

> https://builds.apache.org/view/A-D/view/Derby/job/Derby-trunk-JaCoCo/49/

This build correctly used Java 9.

But it did not run successfully. The output said things like:

[java] Java Result: 134
[junit] Exception in thread "main" java.lang.reflect.InvocationTargetException
[junit] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[junit] at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
[junit] at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
[junit] at java.base/java.lang.reflect.Method.invoke(Method.java:564)
[junit] at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:500)
[junit] at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndCallPremain(InstrumentationImpl.java:512)
[junit] Caused by: java.lang.RuntimeException: Class java/util/UUID could not be instrumented.

Here, I see that to support Java 9, we need JaCoCo 0.7.8:
https://groups.google.com/forum/#!msg/jacoco/Zf0Cwj13G2g/wpyrYAEECAAJ

But it looks like the Jenkins job is using 0.7.6:

++ cat jacocoversion.txt
+ echo 'JaCoCo version: 0.7.6.201602180812'
JaCoCo version: 0.7.6.201602180812

Rick, this one you probably have to track as a separate issue in JIRA; I don't think I can control the JaCoCo version by just changing a Jenkins configuration. Below is what we do in our build, but obviously it didn't automatically move from 0.7.6 to 0.7.8:

1. The files here are supposed to be updated automatically twice a month.
   JACOCO_URL=http://people.apache.org/~kristwaa/derby/jacoco-jars
   #wget -q -O trunk/tools/java/jacocoagent.jar $JACOCO_URL/jacocoagent.jar
   #wget -q -O trunk/tools/java/jacocoant.jar $JACOCO_URL/jacocoant.jar
   #wget -q -O jacocoversion.txt $JACOCO_URL/jacocoversion.txt
   curl $JACOCO_URL/jacocoagent.jar > trunk/tools/java/jacocoagent.jar
   curl $JACOCO_URL/jacocoant.jar > trunk/tools/java/jacocoant.jar
   curl $JACOCO_URL/jacocoversion.txt > jacocoversion.txt

thanks,

bryan