[lldb] Remove unfiltered stop reason propagation from StopInfoMachException (#122817)

In the presence of OS plugins, StopInfoMachException currently
propagates breakpoint stop reasons even if those breakpoints were not
intended for a specific thread, effectively removing our ability to set
thread-specific breakpoints.

This was originally added in [1], but the motivation provided in the
comment does not seem strong enough to remove the ability to set
thread-specific breakpoints. The only way to break thread specific
breakpoints would be if a user set such a breakpoint and _then_ loaded
an OS plugin, a scenario which we would likely not want to support.

[1]:
https://github.com/swiftlang/llvm-project/commit/ab745c2ad865c07f3905482fd071ef36c024713a#diff-8ec6e41b1dffa7ac4b5841aae24d66442ef7ebc62c8618f89354d84594f91050R501

1 files changed, 9 insertions, 0 deletions

diff --git a/lldb/test/API/functionalities/plugins/python_os_plugin/TestPythonOSPlugin.py b/lldb/test/API/functionalities/plugins/python_os_plugin/TestPythonOSPlugin.py
index 479c94c23154..3ad7539018d5 100644
--- a/lldb/test/API/functionalities/plugins/python_os_plugin/TestPythonOSPlugin.py
+++ b/lldb/test/API/functionalities/plugins/python_os_plugin/TestPythonOSPlugin.py
@@ -219,3 +219,12 @@ class PluginPythonOSPlugin(TestBase):
             6,
             "Make sure we stepped from line 5 to line 6 in main.c",
         )
+
+        thread_bp_number = lldbutil.run_break_set_by_source_regexp(
+            self, "Set tid-specific breakpoint here", num_expected_locations=1
+        )
+        breakpoint = target.FindBreakpointByID(thread_bp_number)
+        # This breakpoint should not be hit.
+        breakpoint.SetThreadID(123)
+        process.Continue()
+        self.assertState(process.GetState(), lldb.eStateExited)