Add handling for `STT_TLS` (thread-local storage) symbols in the ELF
symbol parsing code. Previously, TLS symbols like `errno` from glibc
were not recognized because `STT_TLS` was not handled in the symbol type
switch statement.
This treats TLS symbols as data symbols (`eSymbolTypeData`), similar to
`STT_OBJECT`. The actual TLS address resolution is already implemented
in `DynamicLoaderPOSIXDYLD::GetThreadLocalData()` which uses the DWARF
`DW_OP_form_tls_address` opcode to calculate thread-local addresses.