[lldb-vscode] Fix an issue where lldb-vscode tries to display a source file for generated code

[ivanhernandez13]

Summary

According to
https://github.com/llvm/llvm-project/blob/fbcefff9d0a3f5e97270ef8e7b8e0f2afc33dc1c/lldb/source/Symbol/LineEntry.cpp#L215,
a line entry of 0 indicates compiler generated code. Despite it
being generated code, the SBLineEntry.GetFileSpec().IsValid() check
can be true in which case lldb-vscode responds with a non-existent
file named "<compiler-generated>". This patch will instead have
lldb-vscode return the disassembly of the generated code.

[clayborg]

Change looks good. It would be nice to test this if possible.

lldb/tools/lldb-vscode/JSONUtils.cpp

llvm::json::Value CreateSource(llvm::StringRef source_path) {
   EmplaceSafeString(source, "name", name);
   EmplaceSafeString(source, "path", source_path);
   return llvm::json::Value(std::move(source));
 }
 
 llvm::json::Value CreateSource(lldb::SBFrame &frame, int64_t &disasm_line) {
   disasm_line = 0;
   auto line_entry = frame.GetLineEntry();
-  if (line_entry.GetFileSpec().IsValid())
+  if (line_entry.GetFileSpec().IsValid() && line_entry.GetLine() != 0)
     return CreateSource(line_entry);
 
   llvm::json::Object object;
   const auto pc = frame.GetPC();
 
   lldb::SBInstructionList insts;
   lldb::SBFunction function = frame.GetFunction();
   lldb::addr_t low_pc = LLDB_INVALID_ADDRESS;