RFR: 8253795: Implementation of JEP 391: macOS/AArch64 Port [v14]

[Anton Kozlov]

> Please review the implementation of JEP 391: macOS/AArch64 Port.
> 
> It's heavily based on existing ports to linux/aarch64, macos/x86_64, and windows/aarch64. 
> 
> Major changes are in:
> * src/hotspot/cpu/aarch64: support of the new calling convention (subtasks JDK-8253817, JDK-8253818)
> * src/hotspot/os_cpu/bsd_aarch64: copy of os_cpu/linux_aarch64 with necessary adjustments (JDK-8253819)
> * src/hotspot/share, test/hotspot/gtest: support of write-xor-execute (W^X), required on macOS/AArch64 platform. It's implemented with pthread_jit_write_protect_np provided by Apple. The W^X mode is local to a thread, so W^X mode change relates to the java thread state change (for java threads). In most cases, JVM executes in write-only mode, except when calling a generated stub like SafeFetch, which requires a temporary switch to execute-only mode. The same execute-only mode is enabled when a java thread executes in java or native states. This approach of managing W^X mode turned out to be simple and efficient enough.
> * src/jdk.hotspot.agent: serviceability agent implementation (JDK-8254941)

Anton Kozlov has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 73 commits:

 - Merge remote-tracking branch 'upstream/jdk/master' into jdk-macos
   
   Additional work for JDK-8253817: Support macOS Aarch64 ABI in
   Interpreter
 - JDK-8257882: oops, fixed 7fe50a996b6f436932452d220b351c73153ed945
 - Update signal handler part for debugger
 - Cleanup SA changes
 - Merge remote-tracking branch 'origin/jdk/jdk-macos' into jdk-macos
 - support macos_aarch64 in hsdis
 - Merge branch 'master' into jdk-macos
 - Update copyright year for BsdAARCH64ThreadContext.java
 - Fix inclusing of StubRoutines header
 - Redo buildsys fix
 - ... and 63 more: https://git.openjdk.java.net/jdk/compare/40ae9937...4094f351

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Changes: https://git.openjdk.java.net/jdk/pull/2200/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=2200&range=13
  Stats: 3066 lines in 84 files changed: 2954 ins; 47 del; 65 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2200.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2200/head:pull/2200

PR: https://git.openjdk.java.net/jdk/pull/2200