[UBSan] Fix warning by specifying __extension__ before __int128

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@195648 91177308-0d34-0410-b5e6-96231b3b80d8
[lsan] Unbreak lsan_testlib.cc.

Also, add missing logging output.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@195652 91177308-0d34-0410-b5e6-96231b3b80d8