RFR: 8285386: java/util/HashMap/WhiteBoxResizeTest.java fails in tier7 after JDK-8186958

[Stuart Marks]

Adds `othervm` and `-Xmx2g` options to this test, because the default heap of 768m isn't enough.

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Commit messages:
 - Add -Xmx2g to ensure JVM has enough heap.

Changes: https://git.openjdk.java.net/jdk/pull/8352/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=8352&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8285386
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/8352.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/8352/head:pull/8352

PR: https://git.openjdk.java.net/jdk/pull/8352