Add additional fixtures for FragmentInstance text node support

[jackpope]

Stacked on #35630

• Adds test case for compareDocumentPosition, missing before and also extending to text nodes
• Adds event handling fixture case for text
• Adds getRootNode fixture case for text

[react-sizebot]

Comparing: 875b064...93904e7

Critical size changes

Includes critical production bundles, as well as any change greater than 2%:

Name	+/-	Base	Current	+/- gzip	Base gzip	Current gzip
oss-stable/react-dom/cjs/react-dom.production.js	=	6.84 kB	6.84 kB	=	1.88 kB	1.88 kB
oss-stable/react-dom/cjs/react-dom-client.production.js	=	609.58 kB	609.58 kB	=	107.80 kB	107.80 kB
oss-experimental/react-dom/cjs/react-dom.production.js	=	6.84 kB	6.84 kB	=	1.89 kB	1.88 kB
oss-experimental/react-dom/cjs/react-dom-client.production.js	=	675.51 kB	675.51 kB	=	118.75 kB	118.75 kB
facebook-www/ReactDOM-prod.classic.js	=	695.14 kB	695.14 kB	=	122.19 kB	122.19 kB
facebook-www/ReactDOM-prod.modern.js	=	685.52 kB	685.52 kB	=	120.59 kB	120.59 kB

Significant size changes

Includes any change greater than 0.2%:

(No significant changes)

Generated by 🚫 dangerJS against 93904e7