Debug fixture shouldn't use debug_update() to create vests

[theoreticalbts]

This code, which creates VESTS directly for unit tests, is creating false positives of the new rc_plugin code which finds unexpected changes to VESTS (which indicate a bug in the plugin).

So let's replace this method with a transfer from initminer followed by a normal vesting op.

One problem I encountered implementing this, is that some tests, e.g. withdraw_vesting_apply, will mix this method with other debug updates which causes the op to fail when the debug plugin re-pushes the op with less strict skip flags.

[mvandeberg]

It turns out this solution is something I just came to as a work around to get tests working for #1770