fix a few metrics test issues

Author: duncanpo

test/tmetrics.m

@@ -569,6 +569,9 @@ function testGaugeAddAttributes(testCase)
         function testGetSetMeterProvider(testCase)
             % testGetSetMeterProvider: setting, getting, and unsetting global instance of MeterProvider
 
+            % suppress internal warning logs about repeated shutdown
+            nologs = SuppressInternalLogs; %#ok<NASGU>
+
             mp = opentelemetry.sdk.metrics.MeterProvider(testCase.ShortIntervalReader);
             testCase.applyFixture(MeterProviderFixture(mp));  % set MeterProvider global instance
 
@@ -585,6 +588,9 @@ function testGetSetMeterProvider(testCase)
 
             pause(testCase.WaitTime);
 
+            %Shutdown the Meter Provider
+            verifyTrue(testCase, mp.shutdown());
+            
             %Unset the global meter provider and generate more metrics
             opentelemetry.metrics.Provider.unsetMeterProvider;
             m = opentelemetry.metrics.getMeter(metername);

test/tmetrics_sdk.m

@@ -522,6 +522,7 @@ function testCleanupApi(testCase)
             % Shut down an API meter provider instance
             mp = opentelemetry.sdk.metrics.MeterProvider(testCase.ShortIntervalReader);
             testCase.applyFixture(MeterProviderFixture(mp));  % set MeterProvider global instance
+            clear("mp");
             mp_api = opentelemetry.metrics.Provider.getMeterProvider();
 
             % shutdown the API meter provider through the Cleanup class