Remove last reference to SummaryTracker

[arinwt]

Fixes #3243

Also included another back-compat removal change needed in 0.34. It is a context reload compat test change needed as a result of hot-swap context removal by default. PR for back-compat change: #4765.

[arinwt]

Going to hold this PR until 0.33 is released so that it goes into 0.34 instead.
Currently compatibility requirement is +/- 2 versions, and the original removal happened in 0.31.

[anthony-murphy]

@arinwt can this go in now?

[msfluid-bot]

■ @fluidframework/base-host: No change

Metric Name	Baseline Size	Compare Size	Size Diff
main.js	168.34 KB	168.34 KB	■ No change
Total Size	168.34 KB	168.34 KB	■ No change

⯆ @fluid-example/bundle-size-tests: -83 Bytes

Metric Name	Baseline Size	Compare Size	Size Diff
container.js	193.11 KB	193.02 KB	⯆ -83 Bytes
map.js	45.77 KB	45.77 KB	■ No change
matrix.js	143.98 KB	143.98 KB	■ No change
odspDriver.js	195.24 KB	195.24 KB	■ No change
sharedString.js	158.09 KB	158.09 KB	■ No change
Total Size	736.19 KB	736.11 KB	⯆ -83 Bytes

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Baseline commit: 11f2583

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