Fix explicit constructor warning from cpplint

Bug: 137364733
Test: m
Change-Id: Ia3badccda5e6ca139d889c3c7b5aa8a9ab79ef38
diff --git a/libnativeloader/native_loader_test.cpp b/libnativeloader/native_loader_test.cpp
index 75255b6..46e2780 100644
--- a/libnativeloader/native_loader_test.cpp
+++ b/libnativeloader/native_loader_test.cpp
@@ -92,7 +92,7 @@
 // The actual gmock object
 class MockPlatform : public Platform {
  public:
-  MockPlatform(bool is_bridged) : is_bridged_(is_bridged) {
+  explicit MockPlatform(bool is_bridged) : is_bridged_(is_bridged) {
     ON_CALL(*this, NativeBridgeIsSupported(_)).WillByDefault(Return(is_bridged_));
     ON_CALL(*this, NativeBridgeIsPathSupported(_)).WillByDefault(Return(is_bridged_));
     ON_CALL(*this, mock_get_exported_namespace(_, _))