Fix stack buffer overflow in nc4_check_name()
Fix stack buffer overflow in nc4_check_name()

nc4_check_name() checks that the provided string doesn't exceed NC_MAX_NAME,
but fails to do so after calling nc_utf8_normalize(). This extra check is
needed since a caller of nc4_check_name(), like NC4_def_dim, allocates
norm_name as char norm_name[NC_MAX_NAME + 1]

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=2840
Credit to OSS-Fuzz

Unidata/netcdf-c,Unidata/netcdf-c,Unidata/netcdf-c,Unidata/netcdf-c