Fix/suppress google-explicit-constructor warnings

* 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: I6a755699f83d2d5929c9d4a6884a321110d78cea
diff --git a/opengl/tests/hwc/hwcCommit.cpp b/opengl/tests/hwc/hwcCommit.cpp
index 3686dab..0a6ff55 100644
--- a/opengl/tests/hwc/hwcCommit.cpp
+++ b/opengl/tests/hwc/hwcCommit.cpp
@@ -183,7 +183,7 @@
     uint32_t lower(void) { return _l; }
     uint32_t upper(void) { return _u; }
 
-    operator string();
+    operator string(); // NOLINT(google-explicit-constructor)
 
 private:
     uint32_t _l; // lower
@@ -216,7 +216,9 @@
     static void double2Rational(double f, Range nRange, Range dRange,
                                Rational& lower, Rational& upper);
         
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator string() const;
+    // NOLINTNEXTLINE(google-explicit-constructor)
     operator double() const { return (double) _n / (double) _d; }