tests: use {UBSAN,ASAN}_OPTIONS to abort on error

[N-R-K]

c20991d added -ftrapv, presumably to to catch overflows in the CI, but this doesn't really work because UBSan overrides the trap:

[/tmp]~> cat test.c
#include <limits.h>
int main(void)
{
	int a = 5;
	a += INT_MAX;
	return 0;
}
[/tmp]~> gcc -fsanitize=undefined -ftrapv test.c -o test
[/tmp]~> ./test || echo "FAIL"
test.c:5:4: runtime error: signed integer overflow: 5 + 2147483647 cannot be represented in type 'int'

-fsanitize-trap gives the wanted trapping behavior but it doesn't print any diagnostic message:

[/tmp]~> gcc -fsanitize=undefined -fsanitize-trap test.c -o test
[/tmp]~> ./test || echo "FAIL"
zsh: illegal hardware instruction  ./test
FAIL

it's best to use {ASAN,UBSAN}_OPTIONS env vars to configure it to abort on error. this prints diagnostic and also traps:

[/tmp]~> gcc -fsanitize=undefined test.c -o test
[/tmp]~> UBSAN_OPTIONS='abort_on_error=1:halt_on_error=1' ./test || echo "FAIL"
test.c:5:4: runtime error: signed integer overflow: 5 + 2147483647 cannot be represented in type 'int'
zsh: IOT instruction  UBSAN_OPTIONS='abort_on_error=1:halt_on_error=1' ./test
FAIL

[cdown]

Thank you!