Add barrier to ProcessGroup trampoline (#67236)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/67236
cc pietern mrshenli pritamdamania87 zhaojuanmao satgera rohan-varma gqchen aazzolini osalpekar jiayisuse SciPioneer H-Huang
Test Plan: Imported from OSS
Reviewed By: rohan-varma
Differential Revision: D31916706
Pulled By: mrshenli
fbshipit-source-id: f3d2bcd938a384ec297f4094831c69d4059316bb
