message: [lldb] Fix msan use-of-uninitialized-value in DWARFDebugLine::FileNameEntry.
  lldb/lit/SymbolFile/DWARF/debug-types-expressions.test fails with msan.
  This change fixes the issue by ensuring FileNameEntry::checksum is
  always default-initialized.
diff: @@ -29,7 +29,8 @@ class DWARFDebugLine {
  public:
  // FileNameEntry
  struct FileNameEntry {
  - FileNameEntry() : name(nullptr), dir_idx(0), mod_time(0), length(0) {}
  + FileNameEntry()
  + : name(nullptr), dir_idx(0), mod_time(0), length(0), checksum() {}
  const char *name;
  dw_sleb128_t dir_idx;
  