Added variable equality substitutions back in addition to condition substitution.
Added variable equality substitutions back in addition to condition substitution.


Former-commit-id: 710889b088ed18779fad4363144be8d84f76a21a
darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide