RFR: 8275662: remove test/lib/sun/hotspot

[Coleen Phillimore]

This change removes the last remnants of sun/hotspot/WhiteBox.java and other classes, and uses the versions in jdk/test/whitebox.
I used sed to change sun.hotspot.{gc,code,cpuinfo} to jdk.test.whitebox and deleted the old files and some references to sun.hotspot.
Tested with tier1-4.

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Commit messages:
 - 8275662: remove test/lib/sun/hotspot

Changes: https://git.openjdk.org/jdk/pull/9434/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9434&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8275662
  Stats: 1484 lines in 99 files changed: 0 ins; 1367 del; 117 mod
  Patch: https://git.openjdk.org/jdk/pull/9434.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9434/head:pull/9434

PR: https://git.openjdk.org/jdk/pull/9434