test: update test to me MTKBase compatible

Co-authored-by: Aayush Sabharwal <aayush.sabharwal@gmail.com>

Author: SebastianM-C

lib/ModelingToolkitBase/test/initializationsystem.jl

@@ -2047,7 +2047,7 @@ end
 
     eqs = [
         D(s) ~ v
-        m * D(v) ~ 1 - d * v
+        D(v) ~ (1 - d * v) / m
     ]
 
     sys = mtkcompile(System(eqs, t;