Fix rdi_decompressed_size_from_parsed to account for 8-byte alignment padding

[portbuster1337]

Bug

rdi_decompressed_size_from_parsed computes the decompressed size as:

decompressed_size = raw_data_size + sum(unpacked_size - encoded_size)

This formula assumes sections are packed tightly in the decompressed buffer. However, rdi_decompress_parsed aligns each section's data to 8-byte boundaries with padding, so the actual decompressed buffer is larger than the formula predicts. When callers (radbin.c, dbg_info.c) use this function to allocate the output buffer, the buffer may be too small, causing a heap buffer overflow.

Fix

Replicate the exact layout computation from rdi_decompress_parsed to compute the correct decompressed size:

off = data_section_off + sizeof(RDI_Section) * sections_count;
off = align_up(off, 8);
for each section:
    off += section.unpacked_size;
    off = align_up(off, 8);
return off;