Increment match_calls atomically

This ensures the correctness of the counter value, i.e. the value is the number of calls to the match() method.

runtime/Java/src/org/antlr/v4/runtime/atn/LexerATNSimulator.java

@@ -103,7 +103,9 @@ public class LexerATNSimulator extends ATNSimulator {
 	}
 
 	public int match(CharStream input, int mode) {
+		synchronized (LexerATNSimulator.class) {
 			match_calls++;
+		}
 		this.mode = mode;
 		int mark = input.mark();
 		try {