Improve glyph scaling correction (#4747)

## Summary of the Pull Request
- Improves the correction of the scaling and spacing that is applied to
  glyphs if they are too large or too small for the number of columns that
  the text buffer is expecting

## References
- Supersedes #4438 
Co-authored-by: Mili (Yi) Zhang <milizhang@gmail.com>

- Related to #4704 (#4731)

## PR Checklist
* [x] Closes #696 
* [x] Closes #4375 
* [x] Closes #4708 
* [x] Closes a crash that @DHowett-MSFT complained about with
  `"x" * ($Host.UI.RawUI.BufferSize.Width - 1) + "`u{241b}"`
* [x] Eliminates an exception getting thrown with the U+1F3E0 emoji in
  `_CorrectGlyphRun`
* [x] Corrects several graphical issues that occurred after #4731 was
  merged to master (weird repeats and splits of runs)
* [x] I work here.
* [x] Tested manually versus given scenarios.
* [x] Documentation written into comments in the code.
* [x] I'm a core contributor.

## Detailed Description of the Pull Request / Additional comments
- The `_CorrectGlyphRun` function now walks through and uses the
  `_glyphClusters` map to determine the text span and glyph span for each
  cluster so it can be considered as a single unit for scaling.
- The total number of columns expected across the entire cluster
  text/glyph unit is considered for the available spacing for drawing
- The total glyph advances are summed to see how much space they will
  take
- If more space than necessary to draw, all glyphs in the cluster are
  offset into the center and the extra space is padded onto the advance of
  the last glyph in the range.
- If less space than necessary to draw, the entire cluster is marked for
  shrinking as a single unit by providing the initial text index and
  length (that is back-mapped out of the glyph run) up to the parent
  function so it can use the `_SetCurrentRun` and `_SplitCurrentRun`
  existing functions (which operate on text) to split the run into pieces
  and only scale the one glyph cluster, not things next to it as well.
- The scale factor chosen for shrinking is now based on the proportion
  of the advances instead of going through some font math wizardry
- The parent that calls the run splitting functions now checks to not
  attempt to split off text after the cluster if it's already at the end.
  This was @DHowett-MSFT's crash.
- The split run function has been corrected to fix the `glyphStart`
  position of the back half (it failed to `+=` instead of `=` which
  resulted in duplicated text, sometimes).
- Surrogate pair emoji were not allocating an appropriate number of
  `_textClusterColumns`. The constructor has been updated such that the
  trailing half of surrogate pairs gets a 0 column width (as the lead is
  marked appropriately by the `GetColumns()` function). This was the
  exception thrown.
- The `_glyphScaleCorrections` array stored up over the calls to
  `_CorrectGlyphRun` now uses a struct `ScaleCorrection` as we're up to 3
  values.
- The `ScaleCorrection` values are named to clearly indicate they're in
  relation to the original text span, not the glyph spans.
- The values that are used to construct `ScaleCorrection`s within
  `_CorrectGlyphRun` have been double checked and corrected to not
  accidentally use glyph index/counts when text index/counts are what's
  required.

## Validation Steps Performed
- Tested the utf82.txt file from one of the linked bugs. Looked
  specifically at Burmese through Thai to ensure restoration (for the most
  part) of the behavior
- Ensured that U+1f3e0 emoji (🏠) continues to draw correctly
- Checked Fixedsys Excelsior font to ensure it's not shrinking the line
  with its ligatures
- Checked ligatureness of Cascadia Code font 
- Checked combining characters U+0300-U+0304 with a capital A