cirrus-ci: switch from swtpm to mssim. #759

Job	Run time
build-test (ubuntu-20.04, gcc)	4m 25s
build-test (ubuntu-20.04, clang)	4m 27s
build-test (fedora-32, gcc)	4m 41s
scanbuild	6m 35s
test-fuzz	2m 29s
build-test (fedora-32, clang)	4m 57s
test-coverage	5m 2s
build-test (opensuse-leap, gcc)	4m 27s
test-mbedtls (ubuntu-20.04)	2m 47s
build-test (opensuse-leap, clang)	4m 35s
test-no-crypto-build	1m 17s
test-mbedtls (ubuntu-22.04-mbedtls-3.1)	2m 51s
test-tcti-config	14m 14s
build-test (ubuntu-22.04, gcc)	4m 26s
build-test (ubuntu-22.04, clang)	4m 43s
coverity-test	0s
build-test (alpine-3.15, gcc)	3m 53s
build-test (alpine-3.15, clang)	4m 47s
	1h 20m 36s

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