RFR: 8281631: HashMap copy constructor and putAll can over-allocate table [v33]

[XenoAmess]

> 8281631: HashMap copy constructor and putAll can over-allocate table

XenoAmess has updated the pull request incrementally with two additional commits since the last revision:

 - change KeyStructure to String
 - fix test

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7431/files
  - new: https://git.openjdk.java.net/jdk/pull/7431/files/9b9156c1..51871859

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7431&range=32
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7431&range=31-32

  Stats: 133 lines in 1 file changed: 0 ins; 51 del; 82 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7431.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7431/head:pull/7431

PR: https://git.openjdk.java.net/jdk/pull/7431