RFR: 8282893: Remove MacroAssembler::push/pop_callee_saved_registers

[Thomas Schatzl]

Hi all,

  can I have reviews for this trivial removal of some dead code.

Testing: gha builds, internal x86 builds

Thanks,
  Thomas

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.java.net/jdk/pull/7772/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7772&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8282893
  Stats: 19 lines in 2 files changed: 0 ins; 19 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7772.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7772/head:pull/7772

PR: https://git.openjdk.java.net/jdk/pull/7772