Add x86_64 support for x86 tests am: 0b2c8f9705

Original change: https://android-review.googlesource.com/c/platform/external/linux-kselftest/+/1551519

MUST ONLY BE SUBMITTED BY AUTOMERGER

Change-Id: Ib9749e9098a5c5d6f12ac7d78c7e8f9081a8c5c7