Fix the tests for example user profiles (red-green refactor)

[thadk]

There have been several tests created for XML earning history profiles that we received from the Social Security website. These were merged in #129 but the tests are still "red" in TravisCI because the values from this app do not match the Prototype Observable Notebook. That is a bit strange because the calculation functions were taken directly out of that, though the AIME function was updated/improved.

Run the tests with npm test.

Test suites

• John Q. Public (Full Retirement.xml) - these work in the observable calculator but we don't really trust the values to be authoritative because it is not a real person and the values in the XML do not match the values for the same earnings in Detailed Calculator linked below. It is not WEP affected.
• Sample 20, this one is from the official Social Security detail calculator Windows app and one of the ones we truly know the values for. It is WEP affected and make sure you notice it has 1,500.00 monthly pension.
• getAIMEFromEarnings test solo function, this is a stripped down example test.

To Do's

• Fix the tests about substantial earnings: getYearsSE() needs to be able to parse the XML-like JSON object, not just simple key-values. Right now it is always returning 20 which is bad.
• (harder) If any differences remain, figure out why any other of the above tests from Improve Test Suite (WIP) #129 are not matching the observable values and make them run green.
• Write a test suite if there isn't one and figure out why people with fewer than 35 years of income cannot use the app in one of the test cases (see AIME Calculations fails on sub-35 earnings records #108)
• (easiest) Add the three new tests below from the Social Security detail calculator

We also have three fresh new files from the detailed calculator at https://cfb-public.slack.com/archives/CRBK25C2G/p1575918023000400 which you could convert to JSON by adding a new cell like fastXml.parse(\` to the observable notebook, running the cell, and clicking the little button on the left to download the JSON and copy/paste it into a test.

[thadk]

@nvanwitt implemented the (easiest) Add the three new tests below from the Social Security detail calculator somewhere at a hacknight. maybe he can push that to https://github.com/nvanwitt/windfall-elimination/commits/dev, otherwise closing this.