ci: use clang18 for msan build #6033

Job	Run time
git_checks	5s
format	27s
CodeQL (cpp)	18m 44s
el8 (el8, icc, mpich)	23m 20s
macos (macos-13, xcode14_2, x64, shared, serial)	13m 27s
el8 (el8, oneapi, mpich)	23m 19s
macos (macos-14, xcode15_4, arm64, shared, serial)	8m 51s
ubuntu (ubuntu20.04, gcc8, mpich)	8m 25s
ubuntu (ubuntu20.04, gcc9, mpich)	15m 50s
windows (win2019, shared, msmpi)	20m 8s
macos (macos-14, xcode15_4, arm64, static, serial)	5m 20s
ubuntu (ubuntu20.04, gcc10, mpich)	23m 19s
windows (win2022, shared, msmpi)	19m 54s
docker (ubuntu-bionic)	7m 23s
ubuntu (ubuntu20.04, clang6, mpich)	7m 45s
windows (win2022, serial, windows-2022, vs2022)	13m 38s
ubuntu (ubuntu20.04, clang10, mpich)	20m 55s
windows (win2022, static, serial, windows-2022, vs2022)	13m 41s
ubuntu (ubuntu20.04, gcc8, ompi)	23m 17s
ubuntu (ubuntu20.04, gcc8, serial)	14m 25s
ubuntu (ubuntu20.04, clang6, ompi)	23m 19s
ubuntu (ubuntu20.04, clang6, serial)	11m 53s
ubuntu (ubuntu20.04, gcc8, serial, static)	9m 15s
ubuntu (ubuntu22.04, rocm, serial, build_only)	2m 55s
ubuntu (ubuntu22.04, gcc11, mpich)	12m 0s
contract (examples)	2m 13s
contract (lammps)	3m 57s
contract (tau)	10m 43s
build_and_test	1s
	5h 58m 29s

Provide feedback