Larger test suite

[lrettig]

Right now we're only testing a few issuance numbers:

economics/rewards/rewards_test.go

Lines 106 to 116 in 045462b

	{0, 477618397593, 477618397593},
	{1, 477618296206, 955236693799},
	{10, 477617383730, 5253796797276},
	{100, 477608259062, 48238946159315},
	{1000, 477517021972, 478045275698980},
	{10000, 476605609108, 4771595353929638},
	{100000, 467586610967, 47258948463689552},
	{1000000, 386270235450, 430330050824675272},
	{10000000, 57171951699, 1980670207293862126},
	{100000000, 289, 2249999998641054202},
	{1000000000, 0, 2250000000000000000},

It would be nice to have a much larger test suite. Saving the results for all ~100M layers would be a lot of data, but we could randomly sample layers, or compress the results somehow, e.g., even just testing against a hash of the correct values.