Fix point rendering
- Point size limits were left at [0,0], forcing all points to zero coverage.
Introduce a config value for the maximum, and plumb this through to drive
physical device limits query.
- Fix all interpolants being replaced with pointcoord
Bug: b/
124177079
Change-Id: I281dd3214537f15858afbd3890cf70f8850fa4aa
Reviewed-on: https://swiftshader-review.googlesource.com/c/25489
Tested-by: Chris Forbes <chrisforbes@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>