coverage: remove empty mapping regions

This patch removes the empty coverage mapping regions.
Those regions were produced by clang's old mapping region generation 
algorithm, but the new algorithm doesn't generate them.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213981 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed