Fixes #2022, do not resume on Android when surfaceChanged

If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.

Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.

test/testautomation_syswm.c

@@ -0,0 +1,61 @@
+/**
+ * SysWM test suite
+ */
+
+#include <stdio.h>
+
+#include "SDL.h"
+#include "SDL_syswm.h"
+#include "SDL_test.h"
+
+/* Test case functions */
+
+/**
+ * @brief Call to SDL_GetWindowWMInfo
+ */
+int
+syswm_getWindowWMInfo(void *arg)
+{
+  SDL_bool result;
+  SDL_Window *window;
+  SDL_SysWMinfo info;
+
+  window = SDL_CreateWindow("", 0, 0, 0, 0, SDL_WINDOW_HIDDEN);
+  SDLTest_AssertPass("Call to SDL_CreateWindow()");
+  SDLTest_AssertCheck(window != NULL, "Check that value returned from SDL_CreateWindow is not NULL");
+  if (window == NULL) {
+     return TEST_ABORTED;
+  }
+
+  /* Initialize info structure with SDL version info */
+  SDL_VERSION(&info.version);
+
+  /* Make call */
+  result = SDL_GetWindowWMInfo(window, &info);
+  SDLTest_AssertPass("Call to SDL_GetWindowWMInfo");
+  SDLTest_Log((result == SDL_TRUE) ? "Got window information" : "Couldn't get window information");
+
+  SDL_DestroyWindow(window);
+  SDLTest_AssertPass("Call to SDL_DestroyWindow()");
+
+  return TEST_COMPLETED;
+}
+
+/* ================= Test References ================== */
+
+/* SysWM test cases */
+static const SDLTest_TestCaseReference syswmTest1 =
+        { (SDLTest_TestCaseFp)syswm_getWindowWMInfo, "syswm_getWindowWMInfo", "Call to SDL_GetWindowWMInfo", TEST_ENABLED };
+
+/* Sequence of SysWM test cases */
+static const SDLTest_TestCaseReference *syswmTests[] =  {
+    &syswmTest1, NULL
+};
+
+/* SysWM test suite (global) */
+SDLTest_TestSuiteReference syswmTestSuite = {
+    "SysWM",
+    NULL,
+    syswmTests,
+    NULL
+};