open_ipc_handle should use shm from handle #3307

Job	Run time
Coding style	58s
Build docs	48s
Spellcheck / Run spell check	13s
Fast builds / Fast builds (windows-latest, OFF, ON, OFF)	1s
Fast builds / Fast builds (windows-latest, OFF, OFF, OFF)	1s
Fast builds / Fast builds (ubuntu-latest, ON, ON, -DCMAKE_BUILD_TYPE=Release -DUMF_BUILD_BENCHMARKS=ON -DUMF_BU...	1s
Fast builds / Fast builds (ubuntu-latest, OFF, OFF, -DCMAKE_BUILD_TYPE=Release -DUMF_BUILD_BENCHMARKS=ON, OFF)	1s
Fast builds / Fast builds (ubuntu-latest, OFF, ON, -DCMAKE_BUILD_TYPE=Release, ON)	2m 7s
Fast builds / Fast builds (ubuntu-20.04, OFF, ON, -DCMAKE_BUILD_TYPE=Release, ON)	1m 57s
Basic builds	0s
DevDax	0s
Qemu	0s
Sanitizers	0s
ProxyLib	0s
Benchmarks	0s
GPU	0s
Valgrind	0s
MultiNuma	0s
	6m 7s

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