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/utils/LinearAllocator.h b/libs/hwui/utils/LinearAllocator.h
index 03f685e..16cf52f 100644
--- a/libs/hwui/utils/LinearAllocator.h
+++ b/libs/hwui/utils/LinearAllocator.h
@@ -168,7 +168,7 @@
     };
     // enable allocators to be constructed from other templated types
     template <class U>
-    LinearStdAllocator(const LinearStdAllocator<U>& other)  // NOLINT(implicit)
+    LinearStdAllocator(const LinearStdAllocator<U>& other)  // NOLINT(google-explicit-constructor)
             : linearAllocator(other.linearAllocator) {}
 
     T* allocate(size_t num, const void* = 0) {