Fix/suppress hwui google-explicit-constructor warnings

* Add explicit to conversion constructors/operators
* Use NOLINT or NOLINTNEXTLINE to suppress warnings on intended converters

Bug: 28341362
Test: make with WITH_TIDY=1 DEFAULT_GLOBAL_TIDY_CHECKS=-*,google-explicit-constructor
Change-Id: I8c6ebb99679b0a71251024d70a13f8164e67db5e
diff --git a/libs/hwui/Matrix.h b/libs/hwui/Matrix.h
index f0a3a95..9f3c021 100644
--- a/libs/hwui/Matrix.h
+++ b/libs/hwui/Matrix.h
@@ -80,7 +80,7 @@
 
     explicit Matrix4(const float* v) { load(v); }
 
-    Matrix4(const SkMatrix& v) {  // NOLINT, implicit
+    Matrix4(const SkMatrix& v) {  // NOLINT(google-explicit-constructor)
         load(v);
     }