[TableGen] Change names for Builder* and OperationState* parameters to avoid collision

The `Builder*` parameter is unused in both generated build() methods so that we can
leave it unnamed. Changed stand-alone parameter build() to take `_tblgen_state` instead
of `result` to allow `result` to avoid having name collisions with op operand,
attribute, or result.

PiperOrigin-RevId: 240637700