Update `dlmalloc` to 0.1.2
Update `dlmalloc` to 0.1.2

Remove usage of an old and removed wasm intrinsic

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