RFR: 8319115: GrowableArray: Do not initialize up to capacity

[Johan Sjölen]

Hi,

There's no reason to initialize the memory for the elements in the range `[_len, _capacity)` on resize, so let's not do it.

Currently running testing tier1-3.

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Commit messages:
 - Make into one loop
 - Do not init or destruct capacity

Changes: https://git.openjdk.org/jdk/pull/16418/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16418&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8319115
  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/16418.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16418/head:pull/16418

PR: https://git.openjdk.org/jdk/pull/16418