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/tetheroffload/aidl/vts/functional/VtsHalTetheroffloadTargetTest.cpp b/tetheroffload/aidl/vts/functional/VtsHalTetheroffloadTargetTest.cpp
index f46c9ab..1049ea2 100644
--- a/tetheroffload/aidl/vts/functional/VtsHalTetheroffloadTargetTest.cpp
+++ b/tetheroffload/aidl/vts/functional/VtsHalTetheroffloadTargetTest.cpp
@@ -690,6 +690,7 @@
         ::android::PrintInstanceNameToString);
 
 }  // namespace
+}  // namespace aidl::android::hardware::tetheroffload
 
 int main(int argc, char** argv) {
     ::testing::InitGoogleTest(&argc, argv);
@@ -697,5 +698,3 @@
     ABinderProcess_startThreadPool();
     return RUN_ALL_TESTS();
 }
-
-}  // namespace aidl::android::hardware::tetheroffload