removed old coercion code between big decimals and big integers which
should have been removed a long time ago.
fixed test that used to hide the old coercion that was just removed
On the pdb level, the isEqual between real numbers now is fully
structural as it should be. This means that "1.0".isEqual("1.00") will
give false! If you want them to be equal, use the INumber.equal method
instead.

We updated the random tests to use equal instead of isEqual where
necessary.