HDFS-16494.Removed reuse of AvailableSpaceVolumeChoosingPolicy#initLocks().

[jianghuazhu]

Description of PR

When using the default constructor to build the AvailableSpaceVolumeChoosingPolicy, initLocks() is used twice, which is actually unnecessary, the purpose of this pr is to avoid this from happening.
Details: HDFS-16494

How was this patch tested?

Not too stressful for testing. Because this class is relatively mature.

[hadoop-yetus]

💔 -1 overall

Vote	Subsystem	Runtime	Logfile	Comment
+0 🆗	reexec	17m 55s		Docker mode activated.
			_ Prechecks _
+1 💚	dupname	0m 0s		No case conflicting files found.
+0 🆗	codespell	0m 1s		codespell was not available.
+1 💚	@author	0m 0s		The patch does not contain any @author tags.
-1 ❌	test4tests	0m 0s		The patch doesn't appear to include any new or modified tests. Please justify why no new tests are needed for this patch. Also please list what manual steps were performed to verify this patch.
			_ trunk Compile Tests _
+1 💚	mvninstall	34m 48s		trunk passed
+1 💚	compile	1m 29s		trunk passed with JDK Ubuntu-11.0.13+8-Ubuntu-0ubuntu1.20.04
+1 💚	compile	1m 21s		trunk passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	checkstyle	0m 58s		trunk passed
+1 💚	mvnsite	1m 29s		trunk passed
+1 💚	javadoc	1m 3s		trunk passed with JDK Ubuntu-11.0.13+8-Ubuntu-0ubuntu1.20.04
+1 💚	javadoc	1m 27s		trunk passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	spotbugs	3m 25s		trunk passed
+1 💚	shadedclient	25m 38s		branch has no errors when building and testing our client artifacts.
			_ Patch Compile Tests _
+1 💚	mvninstall	1m 17s		the patch passed
+1 💚	compile	1m 25s		the patch passed with JDK Ubuntu-11.0.13+8-Ubuntu-0ubuntu1.20.04
+1 💚	javac	1m 25s		the patch passed
+1 💚	compile	1m 13s		the patch passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	javac	1m 13s		the patch passed
+1 💚	blanks	0m 0s		The patch has no blanks issues.
+1 💚	checkstyle	0m 53s		the patch passed
+1 💚	mvnsite	1m 19s		the patch passed
+1 💚	javadoc	0m 53s		the patch passed with JDK Ubuntu-11.0.13+8-Ubuntu-0ubuntu1.20.04
+1 💚	javadoc	1m 25s		the patch passed with JDK Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
+1 💚	spotbugs	3m 28s		the patch passed
+1 💚	shadedclient	25m 29s		patch has no errors when building and testing our client artifacts.
			_ Other Tests _
-1 ❌	unit	325m 43s	/patch-unit-hadoop-hdfs-project_hadoop-hdfs.txt	hadoop-hdfs in the patch passed.
+1 💚	asflicense	0m 37s		The patch does not generate ASF License warnings.
		450m 30s

Reason	Tests
Failed junit tests	hadoop.hdfs.server.mover.TestMover

Subsystem	Report/Notes
Docker	ClientAPI=1.41 ServerAPI=1.41 base: https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4048/2/artifact/out/Dockerfile
GITHUB PR	#4048
Optional Tests	dupname asflicense compile javac javadoc mvninstall mvnsite unit shadedclient spotbugs checkstyle codespell
uname	Linux e83832001c7d 4.15.0-163-generic #171-Ubuntu SMP Fri Nov 5 11:55:11 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
Build tool	maven
Personality	dev-support/bin/hadoop.sh
git revision	trunk / 57207da
Default Java	Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
Multi-JDK versions	/usr/lib/jvm/java-11-openjdk-amd64:Ubuntu-11.0.13+8-Ubuntu-0ubuntu1.20.04 /usr/lib/jvm/java-8-openjdk-amd64:Private Build-1.8.0_312-8u312-b07-0ubuntu1~20.04-b07
Test Results	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4048/2/testReport/
Max. process+thread count	2343 (vs. ulimit of 5500)
modules	C: hadoop-hdfs-project/hadoop-hdfs U: hadoop-hdfs-project/hadoop-hdfs
Console output	https://ci-hadoop.apache.org/job/hadoop-multibranch/job/PR-4048/2/console
versions	git=2.25.1 maven=3.6.3 spotbugs=4.2.2
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[jianghuazhu]

Here are some unit tests that are failing. E.g:
org.apache.hadoop.hdfs.server.namenode.TestFileTruncate
org.apache.hadoop.hdfs.server.mover.TestMover

It looks like these exceptions have little to do with the update I submitted.
Can you help review this pr, @aajisaka @virajjasani @tomscut .
Thank you very much.

[tomscut]

LGTM.

[jianghuazhu]

Thanks @tomscut .

[jianghuazhu]

Can you help review this pr, @Hexiaoqiao @ferhui .
Thank you very much.

[Hexiaoqiao]

LGTM. +1.

[jianghuazhu]

Thanks @Hexiaoqiao .

[Hexiaoqiao]

Committed to trunk. Thanks @jianghuazhu for your contributions! Thanks @tomscut reviews!