Remove getEstimatedClockResolution from Timer

It used to be part of the experimental benchmarking support, but
since that was replaced with proper benchmarking support with its
own timer facilities, it is now a dead code and useless.

src/catch2/catch_timer.cpp

@@ -17,42 +17,6 @@ namespace Catch {
         return std::chrono::duration_cast<std::chrono::nanoseconds>( std::chrono::high_resolution_clock::now().time_since_epoch() ).count();
     }
 
-    namespace {
-        auto estimateClockResolution() -> uint64_t {
-            uint64_t sum = 0;
-            static const uint64_t iterations = 1000000;
-
-            auto startTime = getCurrentNanosecondsSinceEpoch();
-
-            for( std::size_t i = 0; i < iterations; ++i ) {
-
-                uint64_t ticks;
-                uint64_t baseTicks = getCurrentNanosecondsSinceEpoch();
-                do {
-                    ticks = getCurrentNanosecondsSinceEpoch();
-                } while( ticks == baseTicks );
-
-                auto delta = ticks - baseTicks;
-                sum += delta;
-
-                // If we have been calibrating for over 3 seconds -- the clock
-                // is terrible and we should move on.
-                // TBD: How to signal that the measured resolution is probably wrong?
-                if (ticks > startTime + 3 * nanosecondsInSecond) {
-                    return sum / ( i + 1u );
-                }
-            }
-
-            // We're just taking the mean, here. To do better we could take the std. dev and exclude outliers
-            // - and potentially do more iterations if there's a high variance.
-            return sum/iterations;
-        }
-    }
-    auto getEstimatedClockResolution() -> uint64_t {
-        static auto s_resolution = estimateClockResolution();
-        return s_resolution;
-    }
-
     void Timer::start() {
        m_nanoseconds = getCurrentNanosecondsSinceEpoch();
     }

src/catch2/catch_timer.hpp

@@ -13,7 +13,6 @@
 namespace Catch {
 
     auto getCurrentNanosecondsSinceEpoch() -> uint64_t;
-    auto getEstimatedClockResolution() -> uint64_t;
 
     class Timer {
         uint64_t m_nanoseconds = 0;