[FLINK-12550] fix local input split assignment for hostnames containing a dot (".")

[felse]

What is the purpose of the change

LocatableInputSplitAssigner does not assign input splits locally if the hostname contains a dot ("."), like in hostname.domain. This PR should fix this issue.

Brief change log

• The hostnames of the input split locations are now prepared in the same way as the hostname of the TaskManager that is getting the next input split, before they are compared to each other.
• LocatableInputSplitAssigner and LocatableSplitAssignerTest are reformatted to match code style requirements.

Verifying this change

A unit test has been added (testLocalSplitAssignmentForHostWithDomainName in LocatableSplitAssignerTest). This test fails with all previous versions of LocatableInputSplitAssigner and passes with the change introcuced in this PR.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): (no)
• The public API, i.e., is any changed class annotated with @Public(Evolving): (no)
• The serializers: (no)
• The runtime per-record code paths (performance sensitive): (no)
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Yarn/Mesos, ZooKeeper: (no)
• The S3 file system connector: (no)

Documentation

• Does this pull request introduce a new feature? (no)
• If yes, how is the feature documented? (not applicable)

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[zentol]

please revert all the formatting changes