RFR: 8302685: Some javac unit tests aren't reliably closing open files [v2]

[Archie L. Cobbs]

> Some javac unit tests aren't reliably closing open files. Many were written prior to (or without utilizing) try-with-resources.
> 
> Leaving files and other resources open can cause problems during automated builds, etc.
> 
> This patch updates these tests to use try-with-resource.
> 
> Side note: there is at least one unit test that intentionally leaves a file open - `diags/examples/ProcUnclosedTypeFiles/processors/AnnoProc.java`.

Archie L. Cobbs has updated the pull request incrementally with one additional commit since the last revision:

  Remove extra whitespace.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/12609/files
  - new: https://git.openjdk.org/jdk/pull/12609/files/e61e5714..40a31c3b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=12609&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=12609&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/12609.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12609/head:pull/12609

PR: https://git.openjdk.org/jdk/pull/12609