RFR: 8291752: AArch64: Remove check_emit_size parameter from trampoline_call

[Evgeny Astigeevich]

`MacroAssembler::trampoline_call` can skip generation of a trampoline stub if C2 phase output is in the checking emitted code size mode. If it is not C2 compilation, `trampoline_call` always generates a trampoline stub. 

`gen_continuation_enter` as a part of C2 compilation needed to disable the functionality above. Now `trampoline_call` has the `check_emit_size` which allows to disable the functionality completely. Its default value is `true` which means the functionality is enabled.

There are problems:
- C2 specific code which must be properly guarded if it is not C2 compilation. The code has the risk of undefined behaviour (UB). It is done with `is_c2_compile`. [JDK-8291654](https://bugs.openjdk.org/browse/JDK-8291654) is an example of changes caused UB.
- The default value of `check_emit_size`. The current value `true` allows C1 to access the C2 specific code. Setting the default value to `false` will require to review and to update every existing use of `trampoline_call`. It will complicate uses of `trampoline_call`: each time a decision needs to be done - use or not use the default.

Summary of changes:
- Have a virtual `emit_trampoline_stub` which is privately overridden in `C2_MacroAssembler`. The overridden  version does not emit a stub if C2 phase output is in the checking emitted code size mode.
- `emit_trampoline_stub` returns `bool` instead of `address` because `address` is only used to check the success of a call.
- `check_emit_size` is removed because it is not needed any more.
- `NativeCall::trampoline_jump`:
    - Changed to return `void` because the result is not used. It was returning the result of `emit_trampoline_stub`.
    - Assert `emit_trampoline_stub`.

Tested with fastdebug/release builds:
- `gtest`: Passed.
- `tier1`...`tier4`: Passed.

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Commit messages:
 - 8291752: AArch64: Remove check_emit_size parameter from trampoline_call

Changes: https://git.openjdk.org/jdk/pull/9782/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=9782&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8291752
  Stats: 76 lines in 7 files changed: 30 ins; 25 del; 21 mod
  Patch: https://git.openjdk.org/jdk/pull/9782.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/9782/head:pull/9782

PR: https://git.openjdk.org/jdk/pull/9782