refactor: restore Executor.execute to synchronous def to match public interface

Author: shuoweil

packages/bigframes/bigframes/session/executor.py

@@ -321,7 +321,7 @@ def to_sql(
         raise NotImplementedError("to_sql not implemented for this executor")
 
     @abc.abstractmethod
-    async def execute(
+    def execute(
         self,
         array_value: bigframes.core.ArrayValue,
         execution_spec: ex_spec.ExecutionSpec,

packages/bigframes/bigframes/testing/polars_session.py

@@ -33,7 +33,7 @@
 class TestExecutor(bigframes.session.executor.Executor):
     compiler = bigframes.core.compile.polars.PolarsCompiler()
 
-    async def execute(
+    def execute(
         self,
         array_value: bigframes.core.ArrayValue,
         execution_spec: bigframes.session.execution_spec.ExecutionSpec,

packages/bigframes/noxfile.py

@@ -1048,7 +1048,7 @@ def mypy(session):
     # Editable mode is not compatible with mypy when there are multiple
     # package directories. See:
     # https://github.com/python/mypy/issues/10564#issuecomment-851687749
-    session.install(".")
+    session.install("--no-cache-dir", ".")
 
     # Just install the dependencies' type info directly, since "mypy --install-types"
     # might require an additional pass.