bpo-38605: Revert making 'from __future__ import annotations' the default (GH-25490)

This reverts commits 044a1048ca and 1be456ae9d, adapting the code to changes that happened after it.

Lib/test/test_coroutines.py

@@ -91,6 +91,10 @@ def test_badsyntax_1(self):
                 pass
             """,
 
+            """async def foo(a:await something()):
+                pass
+            """,
+
             """async def foo():
                 def bar():
                  [i async for i in els]
@@ -295,6 +299,10 @@ def bar():
                    pass
             """,
 
+            """async def foo(a:await b):
+                   pass
+            """,
+
             """def baz():
                    async def foo(a=await b):
                        pass