add cross compiling tests from arm/armv7/i686 #458

Job	Run time
Build	20m 11s
Build vendored (vendored-openssl, g3proxy)	11m 49s
Build vendored (vendored-openssl, g3bench)	8m 32s
Build vendored (vendored-openssl, g3tiles)	10m 48s
Build vendored (vendored-openssl, g3fcgen)	8m 47s
Build vendored (vendored-openssl, g3mkcert)	9m 29s
Build vendored (vendored-openssl, g3keymess)	10m 6s
Build vendored (vendored-tongsuo, g3proxy)	8m 50s
Build vendored (vendored-tongsuo, g3bench)	5m 32s
Build vendored (vendored-tongsuo, g3tiles)	6m 55s
Build vendored (vendored-tongsuo, g3fcgen)	6m 49s
Build vendored (vendored-tongsuo, g3mkcert)	5m 4s
Build vendored (vendored-tongsuo, g3keymess)	6m 1s
Build vendored (vendored-aws-lc, g3proxy)	8m 13s
Build vendored (vendored-aws-lc, g3bench)	8m 14s
Build vendored (vendored-aws-lc, g3tiles)	7m 35s
Build vendored (vendored-aws-lc, g3fcgen)	8m 4s
Build vendored (vendored-aws-lc, g3mkcert)	5m 55s
Build vendored (vendored-aws-lc, g3keymess)	6m 43s
Build vendored (vendored-boringssl, g3proxy)	9m 38s
Build vendored (vendored-boringssl, g3bench)	6m 14s
Build vendored (vendored-boringssl, g3tiles)	4m 51s
Build vendored (vendored-boringssl, g3fcgen)	6m 30s
Build vendored (vendored-boringssl, g3mkcert)	5m 1s
Build vendored (vendored-boringssl, g3keymess)	7m 14s
	3h 23m 5s

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