Fix flaky tests on AArch64
Created by: fhahn
Currently, the following tests are flaky on some AArch64 hardware
code_api|pthreads.pthreads_fork_FLAKY
code_api|linux.sigsuspend
code_api|pthreads.pthreads_exit
code_api|security-common.TestMemProtChg_FLAKY
code_api|pthreads.ptsig_FLAKY
code_api|linux.fib-conflict
code_api|linux.fib-conflict-early