Editing custom selection from autocomplete can clear URL suffix

[bbondy]

Fix #9322

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.

Automated test plan

npm run test -- --grep="keeps url text separate from suffix text"

Reviewer Checklist:

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run individually or as a suite ref
• New files have MPL2 license header

[bsclifton]

While testing, I got this... I seem to remember we had it before (and we may have regressed):

An uncaught exception occurred in the main process Uncaught Exception:
TypeError: parsedUrl.query.split is not a function
    at SearchIndex.tokenizeInput (/Users/clifton/Documents/browser-laptop/app/common/lib/siteSuggestions.js:95:44)
    at /Users/clifton/Documents/browser-laptop/node_modules/bloodhound-js/lib/search_index.js:36:37
    at Array.forEach (<anonymous>)
    at Object.each (/Users/clifton/Documents/browser-laptop/node_modules/bloodhound-js/lib/utils.js:52:16)
    at SearchIndex.add (/Users/clifton/Documents/browser-laptop/node_modules/bloodhound-js/lib/search_index.js:32:7)
    at Bloodhound.add (/Users/clifton/Documents/browser-laptop/node_modules/bloodhound-js/lib/bloodhound.js:110:16)
    at add (/Users/clifton/Documents/browser-laptop/app/common/lib/siteSuggestions.js:113:12)
    at urlBarSuggestionsReducer (/Users/clifton/Documents/browser-laptop/app/browser/reducers/urlBarSuggestionsReducer.js:22:9)
    at reducers.reduce (/Users/clifton/Documents/browser-laptop/js/stores/appStore.js:379:24)
    at Array.reduce (<anonymous>)

IIRC, this showed up when the URL had ? or & in it (it had showed up when we switched to the fastUrl parser). I can't repro though. Something to keep an eye out for (this is logged to console, but I didn't see any impact to the UI)

[bsclifton]

LGTM! Change works good 😄 I did notice something which I believe is unrelated (see comment about TypeError: parsedUrl.query.split is not a function).

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