run: try to save deps before running the command (#3709)

Unlike old `_check_missing_deps`, this also verifies that we are able to
save more complex dependencies such as parameters, where we not only
care about the config file, but also about the parameters in it.

Fixes #3707

tests/func/test_run_single_stage.py

@@ -26,7 +26,6 @@ from dvc.stage.exceptions import (
     StagePathOutsideError,
     StagePathNotFoundError,
     StagePathNotDirectoryError,
-    MissingDep,
 )
 from dvc.system import System
 from dvc.utils import file_md5
@@ -79,7 +78,9 @@ class TestRunEmpty(TestDvc):
 
 class TestRunMissingDep(TestDvc):
     def test(self):
-        with self.assertRaises(MissingDep):
+        from dvc.dependency.base import DependencyDoesNotExistError
+
+        with self.assertRaises(DependencyDoesNotExistError):
             self.dvc.run(
                 cmd="",
                 deps=["non-existing-dep"],