Replace explicitly defined constructors at WebCore/platform/graphics by compiler generated with = default
<rdar://problem/129545769>
Pull request: https://github.com/WebKit/WebKit/pull/29696
Committed 279930@main (26e12e7e1938): <https://commits.webkit.org/279930@main> Reviewed commits have been landed. Closing PR #29696 and removing active labels.