HADOOP-16128 Fix FileSystem.newInstance resource leaks in unit tests

[amitvc]

Motivation -
Fix resource leak created in unit tests that instantiate FileSystem resource.

Result -
Fixed the resource leaks in the unit test for the S3A module. Run all unit tests locally successfully.

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	12m 23s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 0s		codespell was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
+1 💚	test4tests	0m 0s		The patch appears to include 2 new or modified test files.
			_ trunk Compile Tests _
+1 💚	mvninstall	30m 50s		trunk passed
+1 💚	compile	0m 47s		trunk passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	compile	0m 40s		trunk passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	checkstyle	0m 32s		trunk passed
+1 💚	mvnsite	0m 47s		trunk passed
+1 💚	javadoc	0m 27s		trunk passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	javadoc	0m 35s		trunk passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	spotbugs	1m 12s		trunk passed
+1 💚	shadedclient	14m 21s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	0m 35s		the patch passed
+1 💚	compile	0m 36s		the patch passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	javac	0m 36s		the patch passed
+1 💚	compile	0m 45s		the patch passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	javac	0m 45s		the patch passed
-1 ❌	blanks	0m 0s	/blanks-eol.txt	The patch has 7 line(s) that end in blanks. Use git apply --whitespace=fix <<patch_file>>. Refer https://git-scm.com/docs/git-apply
-0 ⚠️	checkstyle	0m 26s	/results-checkstyle-hadoop-tools_hadoop-aws.txt	hadoop-tools/hadoop-aws: The patch generated 24 new + 2 unchanged - 0 fixed = 26 total (was 2)
+1 💚	mvnsite	0m 37s		the patch passed
+1 💚	javadoc	0m 16s		the patch passed with JDK Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04
+1 💚	javadoc	0m 26s		the patch passed with JDK Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
+1 💚	spotbugs	1m 12s		the patch passed
+1 💚	shadedclient	14m 2s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
+1 💚	unit	2m 13s		hadoop-aws in the patch passed.
+1 💚	asflicense	0m 35s		The patch does not generate ASF License warnings.
		85m 4s

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3237/1/artifact/out/Dockerfile
GITHUB PR	#3237
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell
uname	Linux fc7c4833414b 4.15.0-112-generic #113-Ubuntu SMP Thu Jul 9 23:41:39 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / 11c287b
Default Java	Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.11+9-Ubuntu-0ubuntu2.20.04 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_292-8u292-b10-0ubuntu1~20.04-b10
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3237/1/testReport/
Max. process+thread count	543 (vs. ulimit of 5500)
modules	C: hadoop-tools/hadoop-aws U: hadoop-tools/hadoop-aws
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-3237/1/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
Powered by	Apache Yetus 0.14.0-SNAPSHOT https://yetus.apache.org

This message was automatically generated.

[amitvc]

I am fixing the build failures. Will push another revision.