RFR: 8186958: Need method to create pre-sized HashMap

[XenoAmess]

8186958: Need method to create pre-sized HashMap

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Commit messages:
 - 8186958: Need method to create pre-sized HashMap

Changes: https://git.openjdk.java.net/jdk/pull/7928/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7928&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8186958
  Stats: 169 lines in 2 files changed: 169 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7928.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7928/head:pull/7928

PR: https://git.openjdk.java.net/jdk/pull/7928