Fix the hidden main function in VTS tests

Otherwise gtest will inherit the one from libgtest_main which
will not start thread pool to handle binder call for callbacks

Bug: b/205762943
Test: atest VtsHalThermalTargetTest VtsHalPowerTargetTest VtsHalTetheroffloadTargetTest
Change-Id: Ib9e5d265b8f5081dd20568a98d01e9190177440a
diff --git a/thermal/aidl/vts/VtsHalThermalTargetTest.cpp b/thermal/aidl/vts/VtsHalThermalTargetTest.cpp
index b93250e..feb4fb1 100644
--- a/thermal/aidl/vts/VtsHalThermalTargetTest.cpp
+++ b/thermal/aidl/vts/VtsHalThermalTargetTest.cpp
@@ -133,6 +133,7 @@
         ::android::PrintInstanceNameToString);
 
 }  // namespace
+}  // namespace aidl::android::hardware::thermal
 
 int main(int argc, char** argv) {
     ::testing::InitGoogleTest(&argc, argv);
@@ -140,5 +141,3 @@
     ABinderProcess_startThreadPool();
     return RUN_ALL_TESTS();
 }
-
-}  // namespace aidl::android::hardware::thermal