[lworld] RFR: 8264897: [lworld] C2: Use BarrierSetC2::obj_allocate to buffer inline type in PhaseMacroExpand::expand_mh_intrinsic_return [v2]

[Yi Yang]

> Try to reuse existing BarrierSetC2::obj_allocate functionality for PhaseMacroExpand::expand_mh_intrinsic_return.
> 
> Testing: x86_64 + linux+ slowdebug/release
> [x] test/hotspot/jtreg/runtime/valhalla 
> [x] test/hotspot/jtreg/compiler/valhalla 
> 
> Thanks,
> Yang

Yi Yang has updated the pull request incrementally with two additional commits since the last revision:

 - more cleanup
 - eliminate nits

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

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/385/files
  - new: https://git.openjdk.java.net/valhalla/pull/385/files/5e88e8a0..863e3504

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=385&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=385&range=00-01

  Stats: 16 lines in 1 file changed: 6 ins; 0 del; 10 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/385.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/385/head:pull/385

PR: https://git.openjdk.java.net/valhalla/pull/385