Use new Computation testing helper function from IEGenLib in spf-ie

[riftEmber]

The Computation::expectEqualTo method that we use in spf-ie tests no longer exists. Need to copy the helper functions expectStmtsEqual and expectComputationsEqual from IEGenLib over to the SPFComputationTest class in spf-ie, then use them in our tests.

[riftEmber]

Forgot to mention, when I say "no longer exists" I mean it doesn't exist in newer commits of IEGenLib -- it exists on the commit we're linked to. As part of this issue you should bump the IEGenLib commit pointer in our CMakeLists to the newest commit on IEGenLib.

[riftEmber]

Did this because I needed it for further development

[kalyanbhetwal]

I implemented the code but realized that it has never been pushed.