Add support for selecting alternate JDWP implementations

Change the '-Xagentlib:jdwp=...' option to instead use the new
'-XjdwpOptions:...' syntax and remove the explicit transport-lib.

Add a '-XjdwpProvider:...' option. Set it to 'default' by default and
get its value from the 'dalvik.vm.jdwp-provider' property.

Test: Boots. Can debug apps
Test: Set dalvik.vm.jdwp-provider=adbconnection, stop, start, debug

Bug: 62821960
Change-Id: I1605030b94b38676c18885fcf2fa3490bccd3e0d