SF: Optionally skip slow unittests

TimeStatsTest::canDumpWithInvalidMaxLayers can take many seconds to run
(even a full minute, depending on the target).

Add a new flag "--no-slow" for libsurfaceflinger_unittests which will
cause it to skip slow tests like these, and add a check to that test
which checks for that flag to skip it.

To run use it with atest, you need to use:

    atest libsurfaceflinger_unittest -- --module-arg libsurfaceflinger_unittest:native-test-flag:--no-slow

Bug: None
Test: atest libsurfaceflinger_unittest

Change-Id: I433c1707eb52866fb9f5c61956db338cc5c58723
diff --git a/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp b/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
index bfd34cd..86f1a39 100644
--- a/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
+++ b/services/surfaceflinger/tests/unittests/TimeStatsTest.cpp
@@ -27,6 +27,8 @@
 
 #include "TimeStats/TimeStats.h"
 
+#include "libsurfaceflinger_unittest_main.h"
+
 using namespace android::surfaceflinger;
 using namespace google::protobuf;
 
@@ -486,6 +488,10 @@
 }
 
 TEST_F(TimeStatsTest, canSurviveMonkey) {
+    if (g_noSlowTests) {
+        GTEST_SKIP();
+    }
+
     EXPECT_TRUE(inputCommand(InputCommand::ENABLE, FMT_STRING).empty());
 
     for (size_t i = 0; i < 10000000; ++i) {