Mouse event helpers missing features

[jsantha]

Event object helpers for creating mouse events miss following features:

• event bubbling
• specifying mouse event button

Quick look at current implementation of Angular CDK library mouse event helpers shows that there is enabled event bubbling by default and you can explicitly specify a mouse button.

Spectator:
https:/NetanelBasal/spectator/blob/master/projects/spectator/src/lib/event-objects.ts#L4

CDK testing
https:/angular/components/blob/master/src/cdk/testing/event-objects.ts#L10

[jsantha]

We need this line as well:
https:/angular/components/blob/master/src/cdk/testing/event-objects.ts#L31

Otherwise the mouseenter event is considered fake, see:
https:/angular/components/blob/master/src/cdk/a11y/fake-mousedown.ts

[NetanelBasal]

Done.