TestConcurrentManyBreakpoints is randomly failing on CI

This test is randomly failing on green dragon with one breakpoint not being detected:

```
FAIL: test (TestConcurrentManyBreakpoints.ConcurrentManyBreakpoints)
Test 100 breakpoints from 100 threads.
----------------------------------------------------------------------
Traceback (most recent call last):
File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/packages/Python/lldbsuite/test/decorators.py", line 160, in wrapper
return func(*args, **kwargs)
File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/test/API/functionalities/thread/concurrent_events/TestConcurrentMa>
self.do_thread_actions(num_breakpoint_threads=100)
File "/Users/ec2-user/jenkins/workspace/llvm.org/as-lldb-cmake/llvm-project/lldb/packages/Python/lldbsuite/test/concurrent_base.py", line 325, in d>
self.assertEqual(
AssertionError: 100 != 99 : Expected 100 breakpoint hits, but got 99
```

Start with TestConcurrentManyBreakpoints in lldb/test/API/functionalities/thread/concurrent_events and the assertion in lldb/packages/Python/lldbsuite/test/concurrent_base.py around line 325. Reproduce the green dragon failure, investigate why one of 100 breakpoint hits is missed, and rerun the test to confirm it no longer fails intermittently.

Written by the indexing model from the issue text.