Bug 1375481 - Removed unnecessary clearings of histograms r=gfritzsche

MozReview-Commit-ID: 3vyJucWa6tq

--HG--
extra : rebase_source : 4259c6d54683d9ca6604a51d018cf3aa5ad9e55b

toolkit/components/telemetry/tests/unit/test_TelemetrySend.js

@@ -325,10 +325,6 @@ add_task(async function test_discardBigPings() {
   // Generate a 2MB string and create an oversized payload.
   const OVERSIZED_PAYLOAD = {"data": generateRandomString(2 * 1024 * 1024)};
 
-  // Reset the histograms.
-  Telemetry.getHistogramById("TELEMETRY_PING_SIZE_EXCEEDED_SEND").clear();
-  Telemetry.getHistogramById("TELEMETRY_DISCARDED_SEND_PINGS_SIZE_MB").clear();
-
   // Submit a ping of a normal size and check that we don't count it in the histogram.
   await TelemetryController.submitExternalPing(TEST_PING_TYPE, { test: "test" });
   await TelemetrySend.testWaitOnOutgoingPings();