Be specific enough that =:= returns true

Refactoring the test suite I found that the old etap was only as strict
as the `==` operator where as EUnit uses the `=:=` operator.

test/cases/doubles.eterm

@@ -1 +1 @@
-[10, 10, 3.141569, 1000].
+[10.0, 10.0, 3.141569, 1.0e3].