Fix length of descriptor field when reading debug info.

TypeIndex is a 16-bit value, and storing kDexNoIndex (0xFFFFFFFF) caused
a failure in a dcheck on the bounds of the value.

Bug: 37287051
Test: mm -j31 test-art-host-gtest-dex_file_test

(cherry-picked from commit c1225361)

Change-Id: If5ae2b624886177d66b3a33ccd75509496deab40