Add OSS-buildbot-style lazy imports test coverage

Summary:
Add OSS-buildbot-style lazy imports test coverage. Itamar [tried](https://www.internalfb.com/diff/D84710473) to do this earlier, but there were some lazy imports test failures.
Almost all of these were test file incompatibilities (e.g. needing to eagerly import inside a test file in order to trigger an `ImportError` that would happen with & without Lazy Imports) and not Lazy Imports issues.
However, one task (T245974066) has been filed to fix a Lazy Imports refleak in the niche case that happens when the subinterpreter creates a lazy object from a Python module (C extensions are fine though), then imports & loads `_testsinglephase` and then loads the lazy object

Reviewed By: itamaro

Differential Revision: D86225881

fbshipit-source-id: 99994f1cffca986d4c3ff75a95b92e68c907a074

Author: Subbarao Garlapati

Lib/bz2.py

@@ -15,7 +15,8 @@
 import os
 
 from _bz2 import BZ2Compressor, BZ2Decompressor
-
+# Meta Lazy Imports compatibility: Force _bz2 to be imported
+BZ2Compressor
 
 # Value 0 no longer used
 _MODE_READ     = 1

Lib/dbm/sqlite3.py

@@ -1,9 +1,15 @@
 import os
-import sqlite3
 from pathlib import Path
 from contextlib import suppress, closing
 from collections.abc import MutableMapping
 
+# Meta Lazy Imports compatibility: Eagerly import `sqlite3` so the ImportError
+# is raised right away
+try:
+    import sqlite3
+except ImportError:
+    raise ImportError("No module named '_sqlite3'")
+
 BUILD_TABLE = """
   CREATE TABLE IF NOT EXISTS Dict (
     key BLOB UNIQUE NOT NULL,

Lib/test/support/__init__.py

@@ -1992,6 +1992,13 @@ def missing_compiler_executable(cmd_names=[]):
     missing.
 
     """
+    try:
+        # FIXME: Eager import `_distutils_hack.override` here, if it exists,
+        # otherwise we can get spurious errors about `No module named 'distutils'`
+        # when importing setuptools.
+        import _distutils_hack.override
+    except ModuleNotFoundError:
+        pass
     from setuptools._distutils import ccompiler, sysconfig
     from setuptools import errors
     import shutil

Lib/test/test_collections.py

@@ -1,6 +1,11 @@
 """Unit tests for collections.py."""
-
-import array
+# Meta Lazy Imports compatibility: Eagerly import `array` so `array.array` is
+# registered with `_collections_abc.Mapping` before refleak tests save ABC state.
+# This is necessary since `dash_R_cleanup()` clears and restores ABC registries.
+try:
+    import array
+except Exception:
+    pass
 import collections
 import copy
 import doctest

Lib/test/test_context.py

@@ -1,7 +1,13 @@
 import sys
 import collections.abc
 import concurrent.futures
-import contextvars
+# Meta Lazy Imports compatibility: Eagerly import contextvars so Context is registered
+# with `_collections_abc.Mapping` before refleak tests save ABC state.
+# This is necessary since `dash_R_cleanup()` clears and restores ABC registries.
+try:
+    import contextvars
+except Exception:
+    pass
 import functools
 import gc
 import random

Lib/test/test_import/__init__.py

@@ -28,7 +28,7 @@
 from unittest import mock
 import _imp
 
-from test.support import os_helper
+from test.support import os_helper, refleak_helper
 from test.support import (
     STDLIB_DIR,
     swap_attr,
@@ -3168,6 +3168,12 @@ def test_check_state_first(self):
 
     @requires_subinterpreters
     def test_basic_multiple_interpreters_main_no_reset(self):
+        # Skip during refleak testing with lazy imports
+        if refleak_helper.hunting_for_refleaks() and importlib.is_lazy_imports_enabled():
+            raise unittest.SkipTest(
+                "TODO(T245974066): Fix Lazy Imports refleak with Single-Phase Initialization Modules"
+            )
+
         # without resetting; already loaded in main interpreter
 
         # At this point:
@@ -3312,6 +3318,12 @@ def test_basic_multiple_interpreters_deleted_no_reset(self):
 
     @requires_subinterpreters
     def test_basic_multiple_interpreters_reset_each(self):
+        # Skip during refleak testing with lazy imports
+        if refleak_helper.hunting_for_refleaks() and importlib.is_lazy_imports_enabled():
+            raise unittest.SkipTest(
+                "TODO(T245974066): Fix Lazy Imports refleak with Single-Phase Initialization Modules"
+            )
+
         # resetting between each interpreter
 
         # At this point: