HBASE-21467 Fix flaky test TestCoprocessorClassLoader.testCleanupOldJars

[OrDTesters]

TestCoprocessorClassLoader.testCleanupOldJars fails when run by itself.

This can be fixed by calling CoprocessorClassLoader.getClassLoader, which initializes the jar file needed by testCleanupOldJars.

Link to issue: HBASE-21467

[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Comment
0	reexec	278	Docker mode activated.
		_ Prechecks _
+1	hbaseanti	0	Patch does not have any anti-patterns.
+1	@author	0	The patch does not contain any @author tags.
+1	test4tests	0	The patch appears to include 1 new or modified test files.
		_ master Compile Tests _
+1	mvninstall	319	master passed
+1	compile	25	master passed
+1	checkstyle	29	master passed
+1	shadedjars	332	branch has no errors when building our shaded downstream artifacts.
+1	findbugs	51	master passed
+1	javadoc	25	master passed
		_ Patch Compile Tests _
+1	mvninstall	315	the patch passed
+1	compile	25	the patch passed
+1	javac	25	the patch passed
+1	checkstyle	28	the patch passed
+1	whitespace	0	The patch has no whitespace issues.
+1	shadedjars	334	patch has no errors when building our shaded downstream artifacts.
+1	hadoopcheck	654	Patch does not cause any errors with Hadoop 2.7.4 or 3.0.0.
+1	findbugs	59	the patch passed
+1	javadoc	23	the patch passed
		_ Other Tests _
+1	unit	188	hbase-common in the patch passed.
+1	asflicense	14	The patch does not generate ASF License warnings.
		2763

Subsystem	Report/Notes
Docker	Client=17.05.0-ce Server=17.05.0-ce base: https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-100/1/artifact/out/Dockerfile
GITHUB PR	#100
Optional Tests	dupname asflicense javac javadoc unit findbugs shadedjars hadoopcheck hbaseanti checkstyle compile
uname	Linux a38276c593df 4.4.0-138-generic #164-Ubuntu SMP Tue Oct 2 17:16:02 UTC 2018 x86_64 GNU/Linux
Build tool	maven
Personality	/testptch/patchprocess/precommit/personality/provided.sh
git revision	master / 11547b7
maven	version: Apache Maven 3.5.4 (1edded0938998edf8bf061f1ceb3cfdeccf443fe; 2018-06-17T18:33:14Z)
Default Java	1.8.0_181
findbugs	v3.1.11
Test Results	https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-100/1/testReport/
Max. process+thread count	290 (vs. ulimit of 10000)
modules	C: hbase-common U: hbase-common
Console output	https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-100/1/console
Powered by	Apache Yetus 0.9.0 http://yetus.apache.org

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[Apache-HBase]

🎊 +1 overall

Vote	Subsystem	Runtime	Comment
0	reexec	21	Docker mode activated.
		_ Prechecks _
+1	hbaseanti	0	Patch does not have any anti-patterns.
+1	@author	0	The patch does not contain any @author tags.
+1	test4tests	0	The patch appears to include 1 new or modified test files.
		_ master Compile Tests _
+1	mvninstall	254	master passed
+1	compile	21	master passed
+1	checkstyle	21	master passed
+1	shadedjars	262	branch has no errors when building our shaded downstream artifacts.
+1	findbugs	42	master passed
+1	javadoc	19	master passed
		_ Patch Compile Tests _
+1	mvninstall	270	the patch passed
+1	compile	23	the patch passed
+1	javac	23	the patch passed
+1	checkstyle	24	the patch passed
+1	whitespace	0	The patch has no whitespace issues.
+1	shadedjars	281	patch has no errors when building our shaded downstream artifacts.
+1	hadoopcheck	534	Patch does not cause any errors with Hadoop 2.7.4 or 3.0.0.
+1	findbugs	50	the patch passed
+1	javadoc	19	the patch passed
		_ Other Tests _
+1	unit	156	hbase-common in the patch passed.
+1	asflicense	10	The patch does not generate ASF License warnings.
		2064

Subsystem	Report/Notes
Docker	Client=17.05.0-ce Server=17.05.0-ce base: https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-100/2/artifact/out/Dockerfile
GITHUB PR	#100
Optional Tests	dupname asflicense javac javadoc unit findbugs shadedjars hadoopcheck hbaseanti checkstyle compile
uname	Linux a9816267dd7e 4.4.0-138-generic #164-Ubuntu SMP Tue Oct 2 17:16:02 UTC 2018 x86_64 GNU/Linux
Build tool	maven
Personality	/testptch/patchprocess/precommit/personality/provided.sh
git revision	master / f30d6c9
maven	version: Apache Maven 3.5.4 (1edded0938998edf8bf061f1ceb3cfdeccf443fe; 2018-06-17T18:33:14Z)
Default Java	1.8.0_181
findbugs	v3.1.11
Test Results	https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-100/2/testReport/
Max. process+thread count	358 (vs. ulimit of 10000)
modules	C: hbase-common U: hbase-common
Console output	https://builds.apache.org/job/HBase-PreCommit-GitHub-PR/job/PR-100/2/console
Powered by	Apache Yetus 0.9.0 http://yetus.apache.org

This message was automatically generated.