RFR: 8256414: add optimized build to submit workflow

[Igor Ignatyev]

Hi all,

Could you please review this small and trivial patch which adds `linux-x64-optimized` build to submit workflow so breakages of this build flavor would be easier to spot?

Thanks,
-- Igor

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Commit messages:
 - add linux-x64-optimized build

Changes: https://git.openjdk.java.net/jdk/pull/1233/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1233&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8256414
  Stats: 4 lines in 1 file changed: 4 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1233.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1233/head:pull/1233

PR: https://git.openjdk.java.net/jdk/pull/1233