paths to test files are too long for windows platforms

[bbauerma]

when trying to install, it fails because of this error:
unable to create file tests/test_data/Sentinel-1_CSAR/IWGRDH/preprocessed/datasets/resam
pled/A0202/EQUI7_EU500M/E006N006T6/sig0/qlooks/Q20160831_163321--_SIG0-----_S1AIWGRDH1VVA_175_A02
01_EU500M_E006N006T6.tif

please shorten this

[bbauerma]

please remove the old "SGRTFilename"-based tests, as the test folder structure is too long for Windows system when trying to install.
Please implement new "YeodaFilename" files for testing, instead.