[sanitizer] Print SIGTRAP for corresponding signal

Reviewers: eugenis, jfb

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D68603

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@373979 91177308-0d34-0410-b5e6-96231b3b80d8