Add report section summarizing failing assertions from all tests in a plan

[mcking65]

On report pages and in candidate review, we need a summary of assertion failures and an easy way to navigate to them.

This summary would include:

1. A heading
2. A summary statement
3. A table of failing assertions

Content for the heading:

Summary of Failing Assertions (n must, n should)

Under the heading, a summary statement of form:

X assertions failed for Y commands in Z tests.

Columns in the table:

1. Test name(make it a link to that test)
2. Command
3. Assertion Priority
4. Assertion (show the phrase form of the assertion)
5. {AT} Response: {AT} is the name of the AT, e.g., "JAWS Response"

In the candidate review experience, this summary would be the first page when the user opens the candidate review experience. It would have its own link at the beginning of the left nav just before test 1. Do not give it a number in the list; just name it "summary of Failing Assertions".

On report pages, this section would appear just after the summary of tests and before test 1.

For example, on the report page JAWS and Chrome for Action Menu Button Example Using aria-activedescendant | ARIA-AT Reports, this section would appear after the section titled "Results for JAWS and Chrome" and before the section titled "Test 1: Navigate forwards to a menu button in reading mode (16 passed, 0 failed)".

Accessibility Note: be sure the table is labeled by the heading.