Don't free aliased pointers in ctx cmp_ctx tests
Coverity recorded issues
1551739 and
1551737, a potential double free in the
tests. It occurs when the DUP operation fails in such a way val3_read is
returned as the same pointer as val2_read. Ideally it should never
happen, but resetting val3_read to 0 should satisfy coverity that there
is no issue here
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Todd Short <todd.short@me.com>
(Merged from https://github.com/openssl/openssl/pull/22800)
(cherry picked from commit
c8ca810da9c47d8cb6988fd14e1cb4e20b0877e8)