RFR: 8290534: Move MacroAssembler::verified_entry to C2_MacroAssembler on x86

[Erik Österlund]

The MacroAssembler::verified_entry method is a C2 function. It belongs in C2_MacroAssembler. This patch moves it there on x86.

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Commit messages:
 - 8290534: Move MacroAssembler::verified_entry to C2_MacroAssembler on x86

Changes: https://git.openjdk.org/jdk/pull/9558/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9558&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8290534
  Stats: 195 lines in 5 files changed: 102 ins; 92 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/9558.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9558/head:pull/9558

PR: https://git.openjdk.org/jdk/pull/9558