outer_boundary_corners and __contains__ raise ValueError on some areas

Checking the outer boundary corners of some areas fails with ValueError. In this case, checking if a certain point is contained also fails.

Code Sample, a minimal, complete, and verifiable piece of code

from pyresample.area_config import parse_area_file
area = parse_area_file(
    "/data/gholl/checkouts/satpy/satpy/etc/areas.yaml",
    "seviri_0deg")[0]
print((0, 0) in area)
print(area.outer_boundary_corners)

Problem description

raises ValueError, probably because the Earth is round and has no corners.

Expected Output

For the outer_boundary_corners, maybe NaN would be appropriate, or maybe a ValueError is actually correct. However, I don't think (lon, lat) in area should raise a ValueError for any valid lon/lat (see also #268). For valid input, this should always return either True or False.

Actual Result, Traceback if applicable

Traceback (most recent call last):
  File "/data/gholl/checkouts/protocode/mwe/outer-corners.py", line 5, in <module>
    print(area.outer_boundary_corners)
  File "/data/gholl/checkouts/pyresample/pyresample/geometry.py", line 2134, in outer_boundary_corners
    return [Coordinate(corner_lons[0], corner_lats[0]),
  File "/data/gholl/checkouts/pyresample/pyresample/spherical_geometry.py", line 50, in __init__
    raise ValueError('Illegal (lon, lat) coordinates: (%s, %s)'
ValueError: Illegal (lon, lat) coordinates: (inf, inf)

Versions of Python, package at hand and relevant dependencies

pyresample v1.22.0-8-gee7c1b9

Reproduce the example using pyresample/geometry.py and inspect how outer_boundary_corners produces coordinates before they are passed to pyresample/spherical_geometry.py:50. Compare that path with the area containment check. Done means valid longitude/latitude input returns True or False from contains, with the intended behavior for invalid outer-boundary corners established.