remove unused executor field

Author: TrevorBergeron

bigframes/session/executor.py

@@ -97,7 +97,6 @@ def __init__(
  *,
  strictly_ordered: bool = True,
  metrics: Optional[bigframes.session.metrics.ExecutionMetrics] = None,
- nondeterminism_only_once: bool = False,
  ):
  self.bqclient = bqclient
  self.storage_manager = storage_manager
@@ -110,7 +109,6 @@ def __init__(
  ] = weakref.WeakKeyDictionary()
  self.metrics = metrics
  self.bqstoragereadclient = bqstoragereadclient
- self.nondeterminism_only_once = (nondeterminism_only_once,)
 
  def to_sql(
  self,