Remove unnecessary memory allocation

Author: adrian-prantl

lib/IRGen/IRGenDebugInfo.cpp

@@ -1532,7 +1532,7 @@ IRGenDebugInfoImpl::IRGenDebugInfoImpl(const IRGenOptions &Opts,
       Opts.DebugInfoLevel > IRGenDebugInfoLevel::LineTables
           ? llvm::DICompileUnit::FullDebug
           : llvm::DICompileUnit::LineTablesOnly);
-  MainFile = getOrCreateFile(BumpAllocatedString(SourcePath));
+  MainFile = getOrCreateFile(SourcePath);
 
   // Because the swift compiler relies on Clang to setup the Module,
   // the clang CU is always created first.  Several dwarf-reading