add type parameters to `BitMatrix` and `SparseBitMatrix` unit tests
add type parameters to `BitMatrix` and `SparseBitMatrix` unit tests

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