Inline PrintingMessageCollector#PLAIN_TEXT_TO_SYSTEM_ERR

Otherwise 'hasErrors' flags was not cleared between subsequent runs of tests
which were using this message collector

compiler/cli/src/org/jetbrains/kotlin/cli/common/messages/PrintingMessageCollector.java

@@ -21,10 +21,6 @@ import org.jetbrains.annotations.NotNull;
 import java.io.PrintStream;
 
 public class PrintingMessageCollector implements MessageCollector {
-    @SuppressWarnings("UseOfSystemOutOrSystemErr")
-    public static final MessageCollector PLAIN_TEXT_TO_SYSTEM_ERR =
-            new PrintingMessageCollector(System.err, MessageRenderer.PLAIN_FULL_PATHS, false);
-
     private final boolean verbose;
     private final PrintStream errStream;
     private final MessageRenderer messageRenderer;