RFR: 8278036: Saving rscratch1 is optional in MacroAssembler::verify_heapbase

[Yi-Fan Tsai]

8278036: Saving rscratch1 is optional in MacroAssembler::verify_heapbase

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Commit messages:
 - Limit the change local
 - Merge branch 'openjdk:master' into pushpop
 - 8278036: Remove redundant push/pop in verify_heapbase

Changes: https://git.openjdk.java.net/jdk/pull/7067/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=7067&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8278036
  Stats: 15 lines in 2 files changed: 11 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7067.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7067/head:pull/7067

PR: https://git.openjdk.java.net/jdk/pull/7067