satpy: autopkgtests run out of memory

[Graham Inggs]

autopkgtests satpy >= 0.19.1 appear to run out of memory on the Ubuntu infrastructure, but pass on Debian CI and for me locally on amd64.
Please hint these tests or add satpy to the big_packages list.

https://ci.debian.net/packages/s/satpy/testing/amd64/

test_load_250m_cloud_mask_dataset (satpy.tests.reader_tests.test_modis_l2.TestModisL2)
Test loading 250m cloud mask. ... DEBUG:satpy.scene:Setting 'PPP_CONFIG_DIR' to 'foo'
DEBUG:satpy.readers:Reading ['/usr/lib/python3/dist-packages/satpy/etc/readers/modis_l2.yaml']
DEBUG:satpy.readers.yaml_reader:Assigning to modis_l2: ['/tmp/tmpz6f7z407/MOD35_L2.A2020045.1719.061.2020045171907.hdf']
DEBUG:satpy.composites:Looking for composites config file modis.yaml
DEBUG:satpy.composites:Looking for composites config file visir.yaml
WARNING:satpy.readers.yaml_reader:Required file type 'hdf_eos_geo' not found or loaded for 'latitude'
WARNING:satpy.readers.yaml_reader:Required file type 'hdf_eos_geo' not found or loaded for 'longitude'
WARNING:satpy.readers.yaml_reader:Failed to load coordinates for 'DatasetID(name='cloud_mask', wavelength=None, resolution=250, polarization=None, calibration=None, level=None, modifiers=())'
Killed
autopkgtest [17:19:09]: test python3: -----------------------]
python3 FAIL non-zero exit status 137

[Steve Langasek (vorlon)]

added to big_packages, so closing as invalid for the package.