Remove personality for declarations in CloneModule.

Personality is copied as part of copyFunctionAttributes, but it is
invalid on a declaration. Remove the personality attribute it the
function body is not cloned.

Also add a verifier run over output modules in the llvm-split tool.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264667 91177308-0d34-0410-b5e6-96231b3b80d8