Add PKCS7_verify corpus #950

Job	Run time
sanity-test-run	1m 56s
macOS-ARM	1s
macOS-x86	1s
macOS-x86-FIPS	1s
macOS-ARM-FIPS	1s
MSVC-2019	1s
MSVC-2022	1s
MSVC-SDE-64-bit	1s
clang-19-pedantic	1s
clang-19-sanity	1s
clang-ubuntu-2004-sanity	1s
clang-ubuntu-2204-sanity	1s
gcc-13-pedantic	1s
gcc-ubuntu-2004-sanity	1s
gcc-4_8	1s
gcc-ubuntu-2204-sanity	1s
gcc-ubuntu-2404-sanity	1s
OpenBSD ${{ matrix.version }} (${{ matrix.arch }}) test	1s
alpine-linux-x86	1s
FreeBSD ${{ matrix.version }} (${{ matrix.arch }}) test	1s
clang-ubuntu-2404-sanity	1s
	2m 16s

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