RFR: 8259713: Fix comments and ResetNoHandleMark in deoptimization

[Coleen Phillimore]

This is a small part of the withdrawn change for https://github.com/openjdk/jdk/pull/1990 to fix the out-of-date comments in deoptimization.cpp.
Tested with tier1-3.

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Commit messages:
 - 8259713: Fix comments and ResetNoHandleMark in deoptimization

Changes: https://git.openjdk.java.net/jdk/pull/2069/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2069&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8259713
  Stats: 11 lines in 1 file changed: 2 ins; 5 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2069.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2069/head:pull/2069

PR: https://git.openjdk.java.net/jdk/pull/2069