Revert "[IR/Verifier] Each DISubprogram with isDefinition: true must belong to a CU."

This reverts commit r266102. The O(N^2) verifier check causes timeouts
in LTO test suite.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@266221 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed