RFR: 8186958: Need method to create pre-sized HashMap [v3]

[XenoAmess]

> 8186958: Need method to create pre-sized HashMap

XenoAmess has updated the pull request incrementally with one additional commit since the last revision:

  move the static functions to map classes themselves.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7928/files
  - new: https://git.openjdk.java.net/jdk/pull/7928/files/78419b28..45f4aae9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7928&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7928&range=01-02

  Stats: 125 lines in 4 files changed: 61 ins; 64 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