[UBSan][boringssl] Temporarily disable UBSan

UBSan was reporting a zero-offset to nullptr. Disable UBSan for this
target for now, then we will come back to fix it once asan-ubsan is
migrated into CQ.

Bug: 46910
Change-Id: Ia46eaf80f8252bbe2731243171b41a1581890ff5
1 file changed