[CodeExtractor] Erase debug intrinsics in outlined thunks (fix PR22900)

Variable updates within the outlined function are invisible to
debuggers. This could be improved by defining a DISubprogram for the
new function. For the moment, simply erase the debug intrinsics instead.

This fixes verifier failures about function-local metadata being used in
the wrong function, seen while testing the hot/cold splitting pass.

rdar://45142482

Differential Revision: https://reviews.llvm.org/D53267

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@344545 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed