NewRadX: Fix reads and writes in emited schedule

[lucass-carneiro]

Currently, given a variable u and its RHS u_rhs, in which NewRadX is applied, we emit schedule statements such as

SCHEDULE NewRadXBoundaryFn_0 IN Foo AFTER Bar
{    
    LANG: C
    Reads: u(Interior)
    Writes: u_rhs(Interior)
} "Desc"

Due to how NewRadX_Apply works, we need to emit

SCHEDULE NewRadXBoundaryFn_0 IN Foo AFTER Bar
{    
    LANG: C
    Reads: u(Interior)
    Reads: u_rhs(Interior)
    Writes: u_rhs(Interior)
} "Desc"