port test_kernels to arraycontext

Author: alexfikl

sumpy/symbolic.py

@@ -137,9 +137,15 @@ def UnevaluatedExpr(x):  # noqa
 
 
 if USE_SYMENGINE:
+    def doit(expr):
+        return expr
+
     def unevaluated_pow(a, b):
         return sym.Pow(a, b)
 else:
+    def doit(expr):
+        return expr.doit()
+
     def unevaluated_pow(a, b):
         return sym.Pow(a, b, evaluate=False)