[lldb] Fix ThreadPlanStepThroughGenericTrampoline

With the rework upstream of step plans, NextRangeBreakpointExplainsStop
was made stateless so the check if the break breakpoints needs to be
cleared needs to be moved to the ShoudStop method.

rdar://159531057
rdar://159675204

Author: augusto2112

lldb/source/Target/ThreadPlanStepThroughGenericTrampoline.cpp

@@ -99,6 +99,8 @@ bool ThreadPlanStepThroughGenericTrampoline::ShouldStop(Event *event_ptr) {
               s.GetData());
   }
 
+  ClearNextBranchBreakpointExplainedStop();
+
   if (IsPlanComplete())
     return true;
 

lldb/test/API/lang/c/trampoline_stepping/TestTrampolineStepping.py

@@ -7,7 +7,6 @@
 from lldbsuite.test.lldbtest import *
 from lldbsuite.test import lldbutil
 
-@skipIf(bugnumber = "rdar://160698178")
 class TestTrampoline(TestBase):
     def setup(self, bkpt_str):
         self.build()
@@ -101,4 +100,4 @@ def test_unused_target(self):
         thread.StepInto()
         name = thread.frames[0].GetFunctionName()
         self.assertIn('unused_target', name)
-        
+

lldb/test/API/lang/swift/cxx_interop/backward/stepping/TestSwiftBackwardInteropStepping.py

@@ -5,7 +5,6 @@
 from lldbsuite.test.lldbtest import *
 from lldbsuite.test.decorators import *
 
-@skipIf(bugnumber="rdar://159531057")
 class TestSwiftBackwardInteropStepping(TestBase):
 
     def setup(self, bkpt_str):