Adjusted the number of test vectors

Adjusted the number of test vectors

There were too many tests vectors.  This is redundant, takes more time
to test, and bloats the generated vectors header file, which then takes
longer to compile.

I reduced their numbers, while making sure they were as effective as
they used to be (maximum code coverage, and every relevant lengths
still tested).

For those who worry about dangerously reducing the number of tests for
Poly1305: don't.  There is nothing the random tests can catch that the
official, hand crafted test vectors cannot.  The random tests don't
really test the core algorithm, they test the loading code.