RFR: 8295808: GrowableArray should support capacity management

[Kim Barrett]

Please review this change to GrowableArray to support capacity management.
Two functions are added to GrowableArray, reserve and shrink_to_fit.  Also
renamed the max_length function to capacity.

Used these new functions in StringDedupTable.

Testing: mach5 tier1-3

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Commit messages:
 - copyrights
 - use reserve/shrink_to_fit in StringDedupTable
 - gtests for capacity functions
 - add reserve and shrink_to_fit
 - max_length() => capacity()
 - initial_capacity => capacity
 - capacity nomenclature

Changes: https://git.openjdk.org/jdk/pull/10827/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10827&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295808
  Stats: 195 lines in 8 files changed: 90 ins; 19 del; 86 mod
  Patch: https://git.openjdk.org/jdk/pull/10827.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10827/head:pull/10827

PR: https://git.openjdk.org/jdk/pull/10827