Added throwUnless and throwUnlessAsync

These are similar to `expect` and `expectAsync` except that they throw
exceptions rather than recording matcher failures as spec/suite failures.
They're intended to support using Jasmine matchers in testing-library's
`waitFor`, and also provide a way to integration-test custom matchers.

These funtions are not equivalent to `expect` and `expectAsync` and should
not be used in situations where you want a matcher failure to reliably fail
the spec. Whether that happens depends on the structure of the surrounding
code. In general, you should only use `throwUnless` when you expect
something (which could be your own code or library code like `waitFor`) to
catch the resulting exception.

Fixes #2003.
Fixes #1980.

package.json

@@ -97,7 +97,8 @@
       ],
       "space-before-blocks": "error",
       "no-eval": "error",
-      "no-var": "error"
+      "no-var": "error",
+      "no-debugger": "error"
     }
   },
   "browserslist": [