Fix dedup regex pattern

This will fix neo4j/neo4j-java-driver#416

community/cypher/cypher-compiler-3.1/src/main/scala/org/neo4j/cypher/internal/compiler/v3_1/planDescription/PlanDescriptionArgumentSerializer.scala

@@ -28,7 +28,7 @@ import org.neo4j.cypher.internal.frontend.v3_1.SemanticDirection
 object PlanDescriptionArgumentSerializer {
   private val SEPARATOR = ", "
   private val UNNAMED_PATTERN = """  (UNNAMED|FRESHID|AGGREGATION)(\d+)""".r
-  private val DEDUP_PATTERN =   """  (.+)@\d+""".r
+  private val DEDUP_PATTERN =   """  ([^\s]+)@\d+""".r
   def serialize(arg: Argument): AnyRef = {
 
     arg match {

community/cypher/cypher-compiler-3.1/src/test/scala/org/neo4j/cypher/internal/compiler/v3_1/planDescription/PlanDescriptionArgumentSerializerTests.scala

@@ -62,4 +62,12 @@ class PlanDescriptionArgumentSerializerTests extends CypherFunSuite {
     serialize(LegacyExpressions(Map("1" -> Literal(42), "2" -> Literal(56)))) should equal(
       "{1 : Literal(42), 2 : Literal(56)}")
   }
+
+  test("serialize something that includes a regex should work") {
+    val value = "GenericCase(Vector((any(  x@40 in n.values where   x@40 =~ Literal(^T-?\\d+$)),SubstringFunction(ContainerIndex(FilterFunction(n.values,  x@106,  x@106 =~ Literal(^T-?\\d+$)),Literal(0)),Literal(1),None))),Some(Literal(1))) == {p0}"
+    serialize(KeyNames(Seq(value))) should equal (
+      "GenericCase(Vector((any(x in n.values where x =~ Literal(^T-?\\d+$)),SubstringFunction(ContainerIndex(FilterFunction(n.values,x,x =~ Literal(^T-?\\d+$)),Literal(0)),Literal(1),None))),Some(Literal(1))) == {p0}"
+    )
+  }
+
 }