Android: Restore generation of non-versioned soname (#15851)

Our check of CMAKE_PLATFORM_NO_VERSIONED_SONAME, originally added by
commit v3.1.0-rc1~416^2 (Add basic Android platform module, 2014-06-06),
was dropped accidentally by commit v3.4.0-rc1~250^2~21
(cmGeneratorTarget: Move GetLibraryNames from cmTarget, 2015-08-04).
Restore the check in the new location of the GetLibraryNames method.