Auto merge of #39874 - amosonn:master, r=alexcrichton
Auto merge of #39874 - amosonn:master, r=alexcrichton

Fixes overflow in libsdt/io/cursor.rs "seek"

Fixes #39631
Test which fails (with old implementation), then fix to implementation.

GBGamer/rust,aidancully/rust,GBGamer/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,aidancully/rust,GBGamer/rust,aidancully/rust,graydon/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,graydon/rust,graydon/rust