Java Signature Help: Add a test file

Author: puremourning

ycmd/tests/java/testdata/extra_confs/simple_extra_conf_project/src/SignatureHelp.java

@@ -0,0 +1,11 @@
+import java.util.function.Function;
+
+public class SignatureHelp
+{
+  public SignatureHelp( String signature ) {
+    this.test( "")
+  }
+
+  public void test( String s, String s ) {
+  }
+}