Revert "[lldb] Store SupportFile in FileEntry (NFC)" (#85885)

Reverts llvm/llvm-project#85468 because @slackito reports this broke
stepping in one of their tests [1] and this patch was meant to be NFC.

[1]
d5a277d309 (commitcomment-139991120)

lldb/source/Commands/CommandObjectBreakpoint.cpp

@@ -780,8 +780,8 @@ private:
       } else {
         const SymbolContext &sc =
             cur_frame->GetSymbolContext(eSymbolContextLineEntry);
-        if (sc.line_entry.GetFile()) {
-          file = sc.line_entry.GetFile();
+        if (sc.line_entry.file) {
+          file = sc.line_entry.file;
         } else {
           result.AppendError("Can't find the file for the selected frame to "
                              "use as the default file.");