Fix dexlayout calculation of code item size.

Calculation of code item size was based on looking for the latest catch
handler referenced by a try block, but there can be handlers that aren't
referenced by any try blocks. This fix manually reads all handlers to
ensure the end is actually reached.

Bug: 35978524
Test: mm test-art-host-gtest-dexlayout_test
Change-Id: I33b30087845f806cd34b888f1ec457ee692f2af4