RFR: 8364150: RISC-V: Leftover for JDK-8343430 removing old trampoline call [v6]

[Fei Yang]

> Hi, please consider this small change.
> 
> JDK-8343430 removed the old trampoline call on RISC-V. And the new solution (reloc call) loads a target address from stub section and do an indirect call. This means the stub is always there for a NativeCall. So there's no need to check existence of the stub when doing `CallRelocation::fix_relocation_after_move` [1].
> 
> We can always return the stub address in `NativeCall::reloc_destination` and use that address in `NativeCall::reloc_set_destination`. This helps simplify the code and saves one `MacroAssembler::target_addr_for_insn` call
> and one `trampoline_stub_Relocation::get_trampoline_for` call in these two functions respectively.
> 
> Testing on linux-riscv64:
> - [x] tier1-tier3 (release build)
> - [x] hs:tier1-hs:tier3 (fastdebug build)
> 
> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/code/relocInfo.cpp#L404-L406

Fei Yang has updated the pull request incrementally with one additional commit since the last revision:

  Review

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26495/files
  - new: https://git.openjdk.org/jdk/pull/26495/files/32ee090f..2839d9d2

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26495&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26495&range=04-05

  Stats: 2 lines in 1 file changed: 2 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26495.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26495/head:pull/26495

PR: https://git.openjdk.org/jdk/pull/26495