The VOP3 form of v_nop now decodes without operands, and no test looked at
it. agc_vop1_control_decode decodes the three instructions in VOP1 and VOP3
form and checks the opcode, the length, the null destination and the absence
of sources. agc_driver_vop1_control also runs v_nop in both forms.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>