RFR: 8293041: --disable- at files option doesn't work and cause an error

[Adam Sotona]

Option --disable- at files is not recognised as valid JVM option, however it is already implemented in the launcher.
Proposed patch skips --disable- at files option in src/hotspot/share/runtime/arguments.cpp processing, so it does not fall into the category of unknown options.
The patch also corrects typo in the launcher.properties and adds simple DisableFilesOptionTest.

Please review.

Thank you,
Adam

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Commit messages:
 - 8293041: --disable- at files option doesn't work and cause an error

Changes: https://git.openjdk.org/jdk/pull/11183/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11183&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8293041
  Stats: 51 lines in 13 files changed: 40 ins; 0 del; 11 mod
  Patch: https://git.openjdk.org/jdk/pull/11183.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11183/head:pull/11183

PR: https://git.openjdk.org/jdk/pull/11183