Output static field values in dexdump

This is necessary to generate table-of-contents of .dex files
to prevent unnecessary rebuilds for implementation-only
changes because these values can be used while compiling other
modules.

Also modify EncodedStaticFieldValueIterator so it can be used
without ClassLoader/Linker.

Bug: 24597504
Change-Id: Ida0c839f9dd6961e1c1b3a380e2092042fad03bb