Disable Hexagon test temporarily.

There is an assert at line 558 in ScheduleDAGInstrs::buildSchedGraph(AliasAnalysis *AA).
This assert needs to addressed for post RA scheduler. Until that assert is addressed,
any passes that uses post ra scheduler will fail. So, I am temporarily disabling the
hexagon tests until that fix is in.

The assert is as follows:
    assert(!MI->isTerminator() && !MI->isLabel() &&
               "Cannot schedule terminators or labels!");

llvm-svn: 154617