this commit restores running the `npm test` command as a part of the
root level package.json's `test.end-to-end` script (and readds it to
CI).

this commit provides support for jest 27 in stencil. this is
accomplished by no longer pulling default options from the jest-cli
package, which now encapsulates its contents through an `exports` field
in its package.json file. during the course of this work, it was
discovered the same fields/defaults were used with Jest 24, 25, & 26.
Those options have been pulled out into a helper function to be provided
for Jest v24 thru 27 to ensure a consistent experience. this helper will
be removed in a future version of Stencil.

the test runner for consumers is locked to jest-jasmine2 for backwards
compatibility in this commit.

jest-runner exposes its default export differently in jest 27. the
creation of a stencil test runner has been updated to handle the
differences between jest v27 and v26 (and under).

jest, jest-cli, jest-environment-node were all updated to the latest
patch version to test with the latest and greatest versions of the
libraries.

update @types/jest to v27, set as recommended version 

add an adr for jest 27 work

this commit adds a simplistic implementation of composedPath.
specifically, it inspects a MockEvent's target, and attempts to
climb the dom to provide the path the event propagates. this
implementation does not take into account closed shadow roots, nor
slots. the reason for which is that unlike a browser, which has far more
knowledge of the dom and event phases, stencil has none of this at the
mock-doc level, making a deep implementation difficult. a fuller
featured version may be considered for a future version of stencil

STENCIL-240: Enhance MockEvent to support composedPath()