Fix assert in XCOFFObjectWriter related to program code csects.
Fix assert in XCOFFObjectWriter related to program code csects.

Removed code that added program code csects to a collection as part
of addressing review comments, but I failed to update an assert affected
by the change before commiting.

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@369471 91177308-0d34-0410-b5e6-96231b3b80d8

GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm