This passes on my Ubuntu box and fails for the commit before issue34537 with the stack trace as per the original report.

karthi@ubuntu-s-1vcpu-1gb-blr1-01:~/cpython$ LC_ALL=C ./python -We -m test -vuall -m test_strings test_gdb
== CPython 3.8.0a0 (heads/master:ea446409cd, Jan 28 2019, 15:07:17) [GCC 5.4.0 20160609]
== Linux-4.4.0-127-generic-x86_64-with-glibc2.17 little-endian
== cwd: /home/karthi/cpython/build/test_python_19425
== CPU count: 1
== encodings: locale=UTF-8, FS=utf-8
Run tests sequentially
0:00:00 load avg: 0.89 [1/1] test_gdb
GDB version 8.2:
    GNU gdb (Ubuntu 8.2-0ubuntu1~16.04.1) 8.2
    Copyright (C) 2018 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.
test_strings (test.test_gdb.PrettyPrintTests)
Verify the pretty-printing of unicode strings ... ok

----------------------------------------------------------------------

Ran 1 test in 3.080s

OK

== Tests result: SUCCESS ==

1 test OK.

Total duration: 3 sec 571 ms
Tests result: SUCCESS
karthi@ubuntu-s-1vcpu-1gb-blr1-01:~/cpython$ git checkout 7279b5125e7c5d84a473d250b27d353cb7f6628e~1 
[...]
karthi@ubuntu-s-1vcpu-1gb-blr1-01:~/cpython$ LC_ALL=C ./python -We -m test -vuall -m test_strings test_gdb
== CPython 3.8.0a0 (heads/master:ea446409cd, Jan 28 2019, 15:07:17) [GCC 5.4.0 20160609]
== Linux-4.4.0-127-generic-x86_64-with-glibc2.17 little-endian
== cwd: /home/karthi/cpython/build/test_python_19484
== CPU count: 1
== encodings: locale=UTF-8, FS=utf-8
Run tests sequentially
0:00:00 load avg: 0.91 [1/1] test_gdb
GDB version 8.2:
    GNU gdb (Ubuntu 8.2-0ubuntu1~16.04.1) 8.2
    Copyright (C) 2018 Free Software Foundation, Inc.
    License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
    This is free software: you are free to change and redistribute it.
    There is NO WARRANTY, to the extent permitted by law.
test_strings (test.test_gdb.PrettyPrintTests)
Verify the pretty-printing of unicode strings ... FAIL

======================================================================
FAIL: test_strings (test.test_gdb.PrettyPrintTests)
Verify the pretty-printing of unicode strings
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/karthi/cpython/Lib/test/test_gdb.py", line 340, in test_strings
    check_repr('\u2620')
  File "/home/karthi/cpython/Lib/test/test_gdb.py", line 332, in check_repr
    self.assertGdbRepr(text)
  File "/home/karthi/cpython/Lib/test/test_gdb.py", line 278, in assertGdbRepr
    self.assertEqual(gdb_repr, exp_repr,
AssertionError: "'\\u2620'" != "'☠'"
- '\u2620'
+ '☠'
 : "'\\u2620'" did not equal expected "'☠'"; full output was:
Breakpoint 1 at 0x5f9036: file Python/bltinmodule.c, line 1178.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".

Breakpoint 1, builtin_id (self=self@entry=, v='\u2620') at Python/bltinmodule.c:1178
1178
#0  builtin_id (self=, v='\u2620') at Python/bltinmodule.c:1178


----------------------------------------------------------------------

Ran 1 test in 1.979s

FAILED (failures=1)
test test_gdb failed
test_gdb failed

== Tests result: FAILURE ==

1 test failed:
    test_gdb

Total duration: 2 sec 576 ms
Tests result: FAILURE