Fix for heap-use-after-free in GPUService.cpp

This adds a unit test and fix for the bug reported by libfuzzer.
Changes made:
 * Expose GPUService as testable code.
 * Update main_gpuservice.cpp to use the new GpuService now located at
   gpuservice/GpuService.h
 * Make initializer threads members of GpuService
 * Join the threads in destructor to prevent heap-use-after-free.
 * Add unit test that waits 3 seconds after deallocation to ensure no
   wrong access is made.

Bug: 282919145
Test: Added unit test and ran on device with ASAN
Change-Id: I4d1d2d4658b575bf2c8f425f91f68f03114ad029
diff --git a/services/gpuservice/tests/fuzzers/GpuServiceFuzzer.cpp b/services/gpuservice/tests/fuzzers/GpuServiceFuzzer.cpp
index c2574a3..241b864 100644
--- a/services/gpuservice/tests/fuzzers/GpuServiceFuzzer.cpp
+++ b/services/gpuservice/tests/fuzzers/GpuServiceFuzzer.cpp
@@ -16,7 +16,7 @@
 
 #include <fuzzbinder/libbinder_driver.h>
 
-#include "GpuService.h"
+#include "gpuservice/GpuService.h"
 
 using ::android::fuzzService;
 using ::android::GpuService;