moveOldFunctionImplementationsToNewSignatures: remove old functions after moving contents to the new ones
moveOldFunctionImplementationsToNewSignatures: remove old functions after moving contents to the new ones

This prevents LLVM from choking to now empty 'declare internal'
functions.

toaarnio/llvm-ir-memprotect,toaarnio/llvm-ir-memprotect,toaarnio/llvm-ir-memprotect,toaarnio/llvm-ir-memprotect