RFR: 8282410: Remove SA ProcDebugger support

[Chris Plummer]

SA has the following source directory:

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/debugger/proc

However, there are no references to any classes in this directory. There used to be a reference to ProcDebuggerLocal, but this reference was removed, along with the class, when solaris support was removed by [JDK-8244224](https://bugs.openjdk.org/browse/JDK-8244224). There appears to be no other need for anything in this directory now, and I believe it can be safely removed.

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Commit messages:
 - Remove ProcDebugger support. Hasn't been needed since Solaris support was removed.

Changes: https://git.openjdk.org/jdk/pull/10013/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10013&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8282410
  Stats: 1655 lines in 23 files changed: 0 ins; 1653 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/10013.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10013/head:pull/10013

PR: https://git.openjdk.org/jdk/pull/10013