BOLT test X86/bb-with-two-tail-calls.s fails in NFC testing

Known issue. The test contains the cold section containing a single nop which gets removed.
BOLT still emits the section with the minimal possible size (1b) but its contents are not initialized.
Therefore the test sporadically fails in buildbot NFC testing, e.g. https://lab.llvm.org/buildbot/#/builders/244/builds/1104