test: run ripple-keypairs tests in the browser (#2558)

- Update tests to use jasmine compatible functions. This means removing `toThrowErrorMatchingInlineSnapshot` and manually removing indention to compare some of the complexly formatted error messages.
- Remove usages of `assert` library in keypairs tests.

packages/ripple-keypairs/test/webpack.config.js

@@ -0,0 +1,9 @@
+'use strict'
+const { merge } = require('webpack-merge')
+const { webpackForTest } = require('../../../weback.test.config')
+const { getDefaultConfiguration } = require('../../../webpack.config')
+
+module.exports = merge(
+  getDefaultConfiguration(),
+  webpackForTest('./test/index.ts', __dirname),
+)