Support SM2 two-party threshold signature #9

Job	Run time
basic_gcc	4m 10s
check_update	1m 21s
check-ansi	1m 53s
minimal	2m 25s
no-deprecated	3m 57s
address_ub_sanitizer	11m 3s
basic_clang	4m 7s
buildtest	6m 36s
enable_non-default_options	3m 33s
fips_and_ktls	4m 14s
legacy	3m 37s
memory_sanitizer	26m 16s
no-legacy	4m 9s
non-caching	4m 13s
no-shared (ubuntu-latest)	3m 15s
no-shared (macos-latest)	7m 45s
ntls_address_ub_sanitizer	9m 44s
ntls_memory_sanitizer	17m 32s
symbol_prefix-test	7m 1s
threads_sanitizer	3m 40s
EC_POINTs_api_test	19m 10s
external-test-pyca (1.51.0, 3.9)	1m 33s
ntls-with-fips	7m 42s
ntls-without-sm234	6m 42s
out-of-source-and-install (ubuntu-latest)	4m 17s
out-of-source-and-install (macos-latest)	10m 32s
phe_test	35m 35s
sm2-threshold-test	43m 36s
smtc_and_ntls	14m 45s
zkp-build-test	3m 17s
	4h 37m 40s

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