Expression 'sigType == TYP_STRUCT' is always false. importer.cpp 18806 (#27292)
Expression 'sigType == TYP_STRUCT' is always false. importer.cpp 18806 (#27292)

`sigType` could be only `TYP_BYREF` or `TYP_REF`, so delete the other cases.
cshung/coreclr,cshung/coreclr,poizan42/coreclr,cshung/coreclr,poizan42/coreclr,poizan42/coreclr,poizan42/coreclr,cshung/coreclr,poizan42/coreclr,poizan42/coreclr,cshung/coreclr,cshung/coreclr