Add a todo item for call and store operand evaluation order.

Author: sunfishcode

ml-proto/TestingTodo.md

@@ -22,6 +22,7 @@ Operator semantics:
  - ~~test that shifts don't mask their shift count. 32 is particularly nice to test.~~
  - test that `page_size` returns a power of 2
  - ~~test that arithmetic operands are evaluated left-to-right~~
+ - test that call and store operands are evaluated left-to-right too
  - ~~test that add/sub/mul/wrap/wrapping-store silently wrap on overflow~~
  - ~~test that sdiv/udiv/srem/urem trap on divide-by-zero~~
  - ~~test that sdiv traps on overflow~~