RFR: 8253162: Make frame::oops_do const [v2]

[Stefan Karlsson]

> Make frame::oops_do const, so that we can use a const frame& receiver when appropriate. With this, we can get rid of
> the temporary copies made just to make the frame variable non-const. See for example:
> https://github.com/openjdk/zgc/blob/c4765b5599d07124410f8a80b1acef9349a998e0/src/hotspot/share/gc/z/zStackWatermark.cpp#L96

Stefan Karlsson has updated the pull request incrementally with one additional commit since the last revision:

  Make frame::oops_do RegisterMap const

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/175/files
  - new: https://git.openjdk.java.net/jdk/pull/175/files/7d44eec8..093bfa91

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=175&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=175&range=00-01

  Stats: 4 lines in 2 files changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/175.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/175/head:pull/175

PR: https://git.openjdk.java.net/jdk/pull/175