Prior to this patch, if a DW_LNE_set_address opcode was parsed with an address size (i.e. with a length after the opcode) of anything other 1, 2, 4, or 8, an llvm_unreachable would be hit, as the data extractor does not support other values. This patch introduces a new error check that verifies the address size is one of the supported sizes, in common with other places within the DWARF parsing.
This patch also fixes calculation of a generated line table's size in unit tests. One of the tests in this patch highlighted a bug introduced in 1271cde4745, when non-byte operands were used as arguments for extended or standard opcodes.