RFR: 8297763: Fix missing stub code expansion before align() in shared trampolines [v2]

[Xiaolin Zheng]

> This patch fixes missing stub code expansion logic before `align()` for AArch64 and RISC-V.
> 
> The `align()` at most creates 4-byte padding, so a `NativeInstruction::instruction_size` is enough.
> 
> I am considering pre-calculating the total trampoline sizes and allocating them in batches, but maybe after this one, for this is a quick fix to unblock https://github.com/openjdk/jdk/pull/11188. Please see that thread.
> 
> The `assert_alignment(pc());` added in the RISC-V part shows that RVC doesn't change the trampoline stub / static stub logic, so there is no need to adjust the trampoline size for it. [1]
> 
> Tested AArch64 hotspot tier1~3, and 4 is still running; tested RISC-V hotspot tier1~2, and 3~4 are still running.
> 
> Thanks,
> Xiaolin
> 
> [1] https://github.com/openjdk/jdk/blob/2deb318c9f047ec5a4b160d66a4b52f93688ec42/src/hotspot/cpu/riscv/macroAssembler_riscv.cpp#L3125-L3126

Xiaolin Zheng has updated the pull request incrementally with one additional commit since the last revision:

  Fix as to comments

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/11414/files
  - new: https://git.openjdk.org/jdk/pull/11414/files/0c031a78..cf0d0372

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11414&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11414&range=00-01

  Stats: 16 lines in 2 files changed: 6 ins; 2 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/11414.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11414/head:pull/11414

PR: https://git.openjdk.org/jdk/pull/11414