[sanitizer] make the deadlock detector print 2*N stack traces on lock-order-inversion with N locks (i.e. print stack traces for both lock acquisitions in every edge in the graph). More improvements to follow

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@204042 91177308-0d34-0410-b5e6-96231b3b80d8