New bytecodes for constant-method-{handle,type}

Adds new bytecodes with const-method-handle and const-method-type for
loading constant method handles and method types. Both bytecodes use
format 21c.

Updates dexdump and libdex to include new bytecodes.

Increases the DEX file version to 039 and API level to 27 for DEX
files using these new bytecodes.

Bug: 66562179
Test: dx/tests/run-test 142
Test: dx/tests/run-all-tests

Change-Id: If349a1e026b2ab604560d200e3c6424378958491