Fix output based test (#5131)

Author: nohwnd

test/Microsoft.TestPlatform.Acceptance.IntegrationTests/DotnetTestMSBuildOutputTests.cs

@@ -33,7 +33,7 @@ public void MSBuildLoggerCanBeEnabledByBuildPropertyAndDoesNotEatSpecialChars(Ru
         // C:\Users\nohwnd\AppData\Local\Temp\vstest\xvoVt\UnitTest1.cs(41): error VSTEST1: (FailingTest) SampleUnitTestProject.UnitTest1.FailingTest() Assert.AreEqual failed. Expected:<2>. Actual:<3>.  [C:\Users\nohwnd\AppData\Local\Temp\vstest\xvoVt\SimpleTestProject.csproj::TargetFramework=net462]
         // C:\Users\nohwnd\AppData\Local\Temp\vstest\xvoVt\UnitTest1.cs(41): error VSTEST1: (FailingTest) SampleUnitTestProject.UnitTest1.FailingTest() Assert.AreEqual failed. Expected:<2>. Actual:<3>.  [C:\Users\nohwnd\AppData\Local\Temp\vstest\xvoVt\SimpleTestProject.csproj::TargetFramework=netcoreapp3.1]
 
-        StdOutputContains("error VSTEST1: FailingTest (");
+        StdOutputContains("error TESTERROR: FailingTest (");
         StdOutputContains("): Error Message: Assert.AreEqual failed. Expected:<ğğğ𦮙我們剛才從𓋴𓅓𓏏𓇏𓇌𓀀>. Actual:<not the same>.");
         StdOutputContains("at TerminalLoggerUnitTests.UnitTest1.FailingTest() in");
         // We are sending those as low prio messages, they won't show up on screen but will be in binlog.