Metric Accumulator fix for SumObservers (#1381)

* Let SynchronizedMove(nil) reset and discard

* Add common test for SynchronizedMove(nil)

* End-to-end test for the Processor and SumObserver

* Implement SynchronizedMove(nil) six ways

* Lint

* Changelog

* Test no reset for wrong aggregator type; Fix four Aggregators

* Cleanup

* imports

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

sdk/metric/aggregator/histogram/histogram_test.go

@@ -24,6 +24,7 @@ import (
 
 	"go.opentelemetry.io/otel/metric"
 	"go.opentelemetry.io/otel/metric/number"
+	export "go.opentelemetry.io/otel/sdk/export/metric"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/aggregatortest"
 	"go.opentelemetry.io/otel/sdk/metric/aggregator/histogram"
 )
@@ -249,3 +250,13 @@ func calcBuckets(points []number.Number, profile aggregatortest.Profile) []uint6
 
 	return counts
 }
+
+func TestSynchronizedMoveReset(t *testing.T) {
+	aggregatortest.SynchronizedMoveResetTest(
+		t,
+		metric.ValueRecorderInstrumentKind,
+		func(desc *metric.Descriptor) export.Aggregator {
+			return &histogram.New(1, desc, boundaries)[0]
+		},
+	)
+}