RFR: 8282770: Set source date in jib profiles from buildId

[Magnus Ihse Bursie]

For reproducability, we should set the source date on jib profiles from the buildId.

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Commit messages:
 - 8282770: Set source date in jib profiles from buildId

Changes: https://git.openjdk.java.net/jdk/pull/7735/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7735&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282770
  Stats: 10 lines in 1 file changed: 8 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7735.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7735/head:pull/7735

PR: https://git.openjdk.java.net/jdk/pull/7735