Fix EVP_PKEY_cmp usage. Not all non-zero values mean success. Flag: EXEMPT CVE_FIX Bug: 469080888 Test: b/469080888#comment6 (cherry picked from commit 8248d2b1f479aebc66ed7d96ba1f19a4144bc537) Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:5c70d050400f748f55f3fce536fb37f37ade9a9f Merged-In: I20f3abf93ab9bd0bd349d17cce2ba7f56fa88e36 Change-Id: I20f3abf93ab9bd0bd349d17cce2ba7f56fa88e36