Revert "Add jit::Type::from method which converts a generic parameter into a JIT type"
Revert "Add jit::Type::from method which converts a generic parameter into a JIT type"

This reverts commit 406de09207d3b1164c9eb7df9b2c3ae94a5cbbf6.

Conflicts:
	src/libjs/run/jit.rs

TomBebbington/jit.rs,tempbottle/jit.rs,bvssvni/jit.rs