PER, UPER: Fix encoding/decoding of open types greater than 16K
Merge branch 'bjorn/asn1/fragmented-open-types/OTP-11223' into maint-r15

* bjorn/asn1/fragmented-open-types/OTP-11223:
  PER, UPER: Fix encoding/decoding of open types greater than 16K
Prepare release
Merge branch 'maint-r15' into maint

Note that this is a fake merge. The bug fix changes files that
are no longer present in maint, and the bug will need to be fixed
in a different way.

* maint-r15:
  Prepare release
  PER, UPER: Fix encoding/decoding of open types greater than 16K
Correct the specifications of io_lib:fread/2,3

Thanks to Chris King and Kostis Sagonas for pinpointing the bug.
Merge branch 'hb/stdlib/correct_fread_spec/OTP-11261' into maint

* hb/stdlib/correct_fread_spec/OTP-11261:
  Correct the specifications of io_lib:fread/2,3