Increase maximum label width by factor of 2

[ChrisLoer]

This is a partial fix for #1531 -- wide labels can still overflow (at which point they stop rendering correctly), but they can now be twice as wide, which will hopefully cover a much wider variety of use cases. #5150 took care of the collision detection problem, so there's no added work necessary for doing collision detection on labels that are wider than the tile's symbol buffers. Also, we no longer use tile clipping for symbols, so there's no problem with labels bleeding far outside their origin tile (err, except for api-gl, wide labels will get rendered-correctly per-tile, but a very wide label in a neighboring tile may be clipped if it doesn't make it into the symbol buffers).

This decreases our glyph-placement precision from 1/64th pixel to 1/32nd pixel, which still seems plenty high. I can't notice any difference in rendering, and all of the render tests pass without change. Doing another halving to 1/16th pixel precision still looks fine to my eyes, but it causes two render tests to fail on (very slight) glyph position changes. For now, 1/32nd seems like a good conservative choice.

Test result before fix:

/cc @ansis @jfirebaugh @james-wagner11

[james-wagner11]

Before:

After:

Thank you @ChrisLoer! I haven't found any labels that still overflow. The additional 2x width makes a big difference for us.

[ChrisLoer]

@james-wagner11 that's great! Thanks for posting those pictures, and happy this turned out to be (knock on wood) an easy one.

[mollymerp]

nice solution! seems very reasonable 👍