Remove files that only exist on <=3.6, update a few comments (#8273)

stdlib/VERSIONS

@@ -63,7 +63,6 @@ ast: 2.7-
 asynchat: 2.7-
 asyncio: 3.4-
 asyncio.mixins: 3.10-
-asyncio.compat: 3.4-3.6
 asyncio.exceptions: 3.8-
 asyncio.format_helpers: 3.7-
 asyncio.runners: 3.7-
@@ -164,7 +163,6 @@ locale: 2.7-
 logging: 2.7-
 lzma: 3.3-
 macpath: 2.7-3.7
-macurl2path: 2.7-3.6
 mailbox: 2.7-
 mailcap: 2.7-
 marshal: 2.7-

stdlib/asyncio/compat.pyi

@@ -1,5 +0,0 @@
-PY34: bool
-PY35: bool
-PY352: bool
-
-def flatten_list_bytes(list_of_data: list[bytes]) -> bytes: ...

stdlib/macurl2path.pyi

@@ -1,5 +0,0 @@
-__all__ = ["url2pathname", "pathname2url"]
-
-def url2pathname(pathname: str) -> str: ...
-def pathname2url(pathname: str) -> str: ...
-def _pncomp2url(component: str | bytes) -> str: ...

stdlib/subprocess.pyi

@@ -67,7 +67,7 @@ _TXT: TypeAlias = bytes | str
 if sys.version_info >= (3, 8):
     _CMD: TypeAlias = StrOrBytesPath | Sequence[StrOrBytesPath]
 else:
-    # Python 3.6 doesn't support _CMD being a single PathLike.
+    # Python 3.7 doesn't support _CMD being a single PathLike.
     # See: https://bugs.python.org/issue31961
     _CMD: TypeAlias = _TXT | Sequence[StrOrBytesPath]
 if sys.platform == "win32":
@@ -704,7 +704,6 @@ elif sys.version_info >= (3, 9):
     ) -> CompletedProcess[Any]: ...
 
 else:
-    # Nearly the same args as for 3.6, except for capture_output and text
     @overload
     def run(
         args: _CMD,

test_cases/README.md

@@ -19,6 +19,6 @@ directory cannot always use modern syntax for type hints. For example, PEP 604
 syntax (unions with a pipe `|` operator) is new in Python 3.10. While this
 syntax can be used on older Python versions in a `.pyi` file, code using this
 syntax will fail at runtime on Python <=3.9. Since the test cases all use `.py`
-extensions, and since the tests need to pass on all Python versions >=3.6, PEP
+extensions, and since the tests need to pass on all Python versions >=3.7, PEP
 604 syntax cannot be used in a test case. Use `typing.Union` and
 `typing.Optional` instead.