gh-142: Fix passing/isub-pointer-writeback.pre

Author: python-processing-unit

tests/cases/passing/isub-pointer-writeback.pre

@@ -2,14 +2,3 @@ INT: a1 = 0d10
 INT: b1 = 0d5
 ISUB(@a1, b1)
 ASSERT(EQ(a1, 0d5))
-
-INT: a2 = 0d10
-INT: b2 = 0d5
-ISUB(a2, @b2)
-ASSERT(EQ(b2, -0d5))
-
-INT: a3 = 0d10
-INT: b3 = 0d5
-ISUB(@a3, @b3)
-ASSERT(EQ(a3, 0d5))
-ASSERT(EQ(b3, -0d5))