[nstepien]

Adds the tests from #4005 that run on main, so that #4005's test changes are limited to the behavior that it changes.

17 tests that pass on main:

• resizable.test.tsx:
  • a new columnWidths map discards the measured and resized widths;
  • without onColumnWidthsChange, the map only sets the initial widths;
  • the widths from the map are clamped;
  • resized widths are kept when the grid is resized, when the maxWidth is lowered temporarily, and when onColumnWidthsChange is removed;
  • auto-sizing that doesn't change a column's width doesn't mark it as resized.
• width.test.tsx, a new file:
  • a new width is used;
  • a column whose width changes from a number to auto is measured;
  • a measured width is kept when the minWidth exceeds it temporarily;
  • opening the grid in a dialog doesn't cause a ResizeObserver loop error;
  • auto columns are at least as wide as their content.
• virtualization.test.ts: columns outside the viewport keep their width, and disabled virtualization works with frozen columns wider than the grid.
• crossWindow.test.tsx: the grid works in a window without ResizeObserver.
• dragFill.test.tsx: the drag handle doesn't get the column's width constraints.
• ssr.test.tsx: all the columns are rendered on the server when virtualization is disabled.

3 tests marked test.fails(), for behavior that #4005 changes. They failed in all three browsers in 5 local runs on main:

• The measured width of a column that isn't rendered is kept in the widths passed to onColumnWidthsChange. Refactor column width and resizing handling #4005 drops it.
• A measured width passed via columnWidths is used as is, e.g., a 1500px column in a 1000px grid. Refactor column width and resizing handling #4005 measures the column again.
• An auto column next to a percentage column that is clamped to its maxWidth is measured as if the percentage column weren't clamped, so the columns leave a gap at the end of the grid.

Left in #4005:

• 2 tests that fail on main only because they check Refactor column width and resizing handling #4005's implementation: that measuring cells are observed with the ResizeObserver of their window, and that column templates are auto while a column is resized.
• 2 tests that sometimes pass on main in Firefox and WebKit, so they can't be marked test.fails(): the grid narrowing with 8 or 12 columns.
• Refactor column width and resizing handling #4005's edits to existing tests.

vp run ci passes.

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