RFR: 8275074: Cleanup unused code in JFR LeakProfiler

[Roman Kennke]

While doing some fixes for Lilliput in JFR I noticed a couple of unused code paths. Let's remove them. 
Specifically, it's the entirety of saveRestore.hpp/cpp and a helper method in edgeUtils.hpp/cpp.

Testing:
 - [x] tier1
 - [x] jdk/jfr

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Commit messages:
 - 8275074: Cleanup unused code in JFR LeakProfiler

Changes: https://git.openjdk.java.net/jdk/pull/5899/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5899&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8275074
  Stats: 245 lines in 4 files changed: 0 ins; 245 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5899.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5899/head:pull/5899

PR: https://git.openjdk.java.net/jdk/pull/5899