I have the same issue on Debian 9:

== CPython 3.8.0a0 (heads/master:874809e, Sep 6 2018, 23:31:00) [GCC 6.3.0 20170516]
== Linux-4.9.0-6-amd64-x86_64-with-glibc2.17 little-endian
== cwd: /home/xxx/xxx/cpython/git/cpython/build/test_python_55266
== CPU count: 4
== encodings: locale=UTF-8, FS=utf-8
Using random seed 1679661
Run tests in parallel using 6 child processes
0:00:00 load avg: 0.35 [1/1/1] test_pkg failed
test_1 (test.test_pkg.TestPkg) ... ok
test_2 (test.test_pkg.TestPkg) ... ok
test_3 (test.test_pkg.TestPkg) ... ok
test_4 (test.test_pkg.TestPkg) ... ERROR
test_5 (test.test_pkg.TestPkg) ... ok
test_6 (test.test_pkg.TestPkg) ... ok
test_7 (test.test_pkg.TestPkg) ... FAIL
test_8 (test.test_pkg.TestPkg) ... ok

======================================================================
ERROR: test_4 (test.test_pkg.TestPkg)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/xxx/xxx/cpython/git/cpython/Lib/test/test_pkg.py", line 180, in test_4
    self.run_code(s)
  File "/home/xxx/xxx/cpython/git/cpython/Lib/test/test_pkg.py", line 69, in run_code
    exec(textwrap.dedent(code), globals(), {"self": self})
  File "<string>", line 2, in <module>
  File "/tmp/tmppheh3y0k/t4.py", line 1, in <module>
RuntimeError: Shouldnt load t4.py

======================================================================
FAIL: test_7 (test.test_pkg.TestPkg)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/xxx/xxx/cpython/git/cpython/Lib/test/test_pkg.py", line 260, in test_7
    '__name__', '__package__', '__path__', '__spec__'])
AssertionError: Lists differ: ['__c[34 chars]__loader__', '__name__', '__package__', '__spec__'] != ['__c[34 chars]__loader__', '__name__', '__package__', '__path__', '__spec__']

First differing element 6:
'__spec__'
'__path__'

Second list contains 1 additional elements.
First extra element 7:
'__spec__'

  ['__cached__',
   '__doc__',
   '__file__',
   '__loader__',
   '__name__',
   '__package__',
+  '__path__',
   '__spec__']

----------------------------------------------------------------------
Ran 8 tests in 0.028s

FAILED (failures=1, errors=1)
test test_pkg failed

== Tests result: FAILURE ==

1 test failed:
    test_pkg