fix amrex_assert on cot

Author: zhichen3

Source/driver/Castro_math.H

@@ -25,8 +25,12 @@ cross_product(amrex::GpuArray<amrex::Real, 3> const& a,
 AMREX_GPU_HOST_DEVICE AMREX_INLINE
 amrex::Real cot(amrex::Real x) {
 
-    AMREX_ASSERT(x != 0.0_rt || x != M_PI);
+    AMREX_ASSERT(x != 0.0_rt && x != M_PI);
+
     // we want to reflect outside of x in [0, pi]
+    // i.e. if x = -0.1 -> x = 0.1
+    // and  if x = 5π/4 -> x = 3π/4
+
     if (x < 0.0_rt || x > M_PI) {
         x = M_PI - x;
     }