[BEAM-1832] Fix for potentially unclosed streams in ApexYarnLauncher

[rekhajoshm]

[BEAM-1832] Fix for potentially unclosed streams in ApexYarnLauncher

• Using try-resources to handle closeable close issue
• Removed redundant semicolons, string null assignment
• Indent/spaces as per beam codestyle. Checkstyle passes. mvn clean verify passes.

[coveralls]

Coverage increased (+0.003%) to 69.817% when pulling 46700c6 on rekhajoshm:BEAM-1832-0 into 37e4cc1 on apache:master.

[asfbot]

Refer to this link for build results (access rights to CI server needed):
https://builds.apache.org/job/beam_PreCommit_Java_MavenInstall/9248/
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[tweise]

@rekhajoshm I don't think it is desirable to reformat entire files to make relatively small changes. It looks like large chunks of code moved around without change. Can you please submit the first 2 items as separate PR that only contains those changes? Thanks!