{LYN-4372} fix for Python exit crash (#1600)

There is a crash when sys.exit() was being called since embedded Python
should not have control of the application lifetime. The Py_InspectFlag
puts the Python VM into 'inspection mode' which prevents the app
shutdown when any sys.exit() is invoked.

Notes:
* skips 'regset' extra command line in PythonBindingsExample
* added methods for handling PythonBindingsExample errors

Test: added Application_SystemExit_Blocked and
fixed up Application_Run_Fails now is Application_Run_Works

Code/Tools/PythonBindingsExample/tests/ApplicationTests.cpp

@@ -58,9 +58,9 @@ namespace PythonBindingsExample
 
     AZStd::unique_ptr<PythonBindingsExample::Application> PythonBindingsExampleTest::s_application;
 
-    TEST_F(PythonBindingsExampleTest, Application_Run_Fails)
+    TEST_F(PythonBindingsExampleTest, Application_Run_Works)
     {
-        EXPECT_FALSE(s_application->Run());
+        EXPECT_TRUE(s_application->Run());
     }
 
     TEST_F(PythonBindingsExampleTest, Application_RunWithParameters_Works)
@@ -90,4 +90,37 @@ namespace PythonBindingsExample
         EXPECT_TRUE(s_application->RunWithParameters(params));
     }
 
+    TEST_F(PythonBindingsExampleTest, Application_SystemExit_Blocked)
+    {
+        int exceptions = 0;
+        int errors = 0;
+
+        s_application->GetErrorCount(exceptions, errors);
+        ASSERT_EQ(exceptions, 0);
+        ASSERT_EQ(errors, 0);
+
+        // expects a clean "error" from this statement
+        // the whole program should not exit()
+        {
+            ApplicationParameters params;
+            params.m_pythonStatement = "import sys; sys.exit(0)";
+            EXPECT_FALSE(s_application->RunWithParameters(params));
+
+            s_application->GetErrorCount(exceptions, errors);
+            EXPECT_EQ(exceptions, 0);
+            EXPECT_GE(errors, 1);
+        }
+        s_application->ResetErrorCount();
+
+        // should be able to run more statements
+        {
+            ApplicationParameters params;
+            params.m_pythonStatement = "import sys";
+            EXPECT_TRUE(s_application->RunWithParameters(params));
+
+            s_application->GetErrorCount(exceptions, errors);
+            EXPECT_EQ(exceptions, 0);
+            EXPECT_EQ(errors, 0);
+        }
+    }
 }