Fix/suppress libs/gui google-explicit-constructor warnings

* Add explicit to conversion constructors/operators

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: I76384db26fac6da2de3dbb9092c26c4979324948
diff --git a/libs/gui/tests/Malicious.cpp b/libs/gui/tests/Malicious.cpp
index bb6b8a5..acd4297 100644
--- a/libs/gui/tests/Malicious.cpp
+++ b/libs/gui/tests/Malicious.cpp
@@ -27,7 +27,7 @@
 
 class ProxyBQP : public BnGraphicBufferProducer {
 public:
-    ProxyBQP(const sp<IGraphicBufferProducer>& producer) : mProducer(producer) {}
+    explicit ProxyBQP(const sp<IGraphicBufferProducer>& producer) : mProducer(producer) {}
 
     // Pass through calls to mProducer
     status_t requestBuffer(int slot, sp<GraphicBuffer>* buf) override {
@@ -102,7 +102,7 @@
 
 class MaliciousBQP : public ProxyBQP {
 public:
-    MaliciousBQP(const sp<IGraphicBufferProducer>& producer) : ProxyBQP(producer) {}
+    explicit MaliciousBQP(const sp<IGraphicBufferProducer>& producer) : ProxyBQP(producer) {}
 
     void beMalicious(int32_t value) { mMaliciousValue = value; }