Add unittests for veristat_compare script #520

Job	Run time
set-matrix	2s
build for x86_64 with gcc	5m 51s
build for x86_64 with llvm-16	6m 6s
build for aarch64 with gcc	5m 57s
build for s390x with gcc	14m 55s
veristat	2m 2s
test_progs on x86_64 with gcc	4m 5s
test_progs_parallel on x86_64 with gcc	2m 32s
test_progs_no_alu32 on x86_64 with gcc	3m 28s
test_progs_no_alu32_parallel on x86_64 with gcc	2m 10s
test_maps on x86_64 with gcc	2m 17s
test_verifier on x86_64 with gcc	1m 12s
test_progs on x86_64 with llvm-16	4m 7s
test_progs_parallel on x86_64 with llvm-16	2m 34s
test_progs_no_alu32 on x86_64 with llvm-16	3m 15s
test_progs_no_alu32_parallel on x86_64 with llvm-16	2m 13s
test_maps on x86_64 with llvm-16	2m 18s
test_verifier on x86_64 with llvm-16	1m 12s
test_progs on aarch64 with gcc	5m 14s
test_progs_parallel on aarch64 with gcc	2m 52s
test_progs_no_alu32 on aarch64 with gcc	4m 36s
test_progs_no_alu32_parallel on aarch64 with gcc	2m 42s
test_maps on aarch64 with gcc	2m 35s
test_verifier on aarch64 with gcc	1m 2s
test_progs on s390x with gcc	31m 28s
test_progs_no_alu32 on s390x with gcc	17m 6s
test_maps on s390x with gcc	20m 44s
test_verifier on s390x with gcc	5m 30s
	2h 40m 5s

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