Add include test for legacy provider #78

Job	Run time
check_docs	1m 9s
check_update	1m 15s
check-ansi	5m 36s
basic_clang	9m 34s
basic_gcc	7m 53s
minimal	4m 10s
no-deprecated	9m 34s
address_ub_sanitizer	15m 25s
buildtest	9m 46s
enable_brotli_and_asan_ubsan	17m 31s
enable_brotli_and_zstd_dynamic	10m 32s
enable_brotli_dynamic	7m 20s
enable_non-default_options	7m 47s
enable_zstd_and_asan_ubsan	17m 23s
enable_zstd_dynamic	7m 48s
enable-tfo (ubuntu-latest)	8m 50s
enable-tfo (macos-latest)	7m 23s
fips_and_ktls	8m 14s
legacy	8m 25s
memory_sanitizer	22m 36s
no-legacy	9m 23s
non-caching	13m 12s
no-shared (ubuntu-latest)	5m 32s
threads_sanitizer	6m 32s
no-shared (macos-latest)	4m 3s
external-test-cf-quiche	7m 49s
external-test-pyca (1.51.0, 3.9)	15m 55s
external-tests	18m 30s
out-of-source-and-install (ubuntu-latest)	6m 49s
out-of-source-and-install (macos-latest)	10m 25s
	4h 46m 21s

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