Eliminate double-spaced output from Textifier

.gitignore

@@ -4,7 +4,11 @@ build/
 
 # Files generated by Eclipse
 **/.classpath
-**/.gitignore
 **/.project
 **/.settings/
 **/bin/
+
+# Files generated by IntelliJ
+.idea/
+out/
+*.iml

asm-util/src/main/java/org/objectweb/asm/util/Textifier.java

@@ -191,13 +191,14 @@ public class Textifier extends Printer {
     if (superName != null && !"java/lang/Object".equals(superName)) {
       stringBuilder.append(" extends ");
       appendDescriptor(INTERNAL_NAME, superName);
-      stringBuilder.append(' ');
     }
     if (interfaces != null && interfaces.length > 0) {
       stringBuilder.append(" implements ");
       for (int i = 0; i < interfaces.length; ++i) {
         appendDescriptor(INTERNAL_NAME, interfaces[i]);
-        stringBuilder.append(' ');
+        if (i != interfaces.length - 1) {
+          stringBuilder.append(' ');
+        }
       }
     }
     stringBuilder.append(" {\n\n");

asm-util/src/test/resources/jdk3.AllStructures$1.txt

 // class version 45.3 (196653)
 // access flags 0x20
-class jdk3/AllStructures$1 implements java/lang/Runnable  {
+class jdk3/AllStructures$1 implements java/lang/Runnable {
 
   // compiled from: AllStructures.java
   // access flags 0x0

asm-util/src/test/resources/jdk3.AllStructures.txt

 // class version 45.3 (196653)
 // access flags 0x420
-abstract class jdk3/AllStructures implements java/lang/Runnable java/lang/Cloneable java/io/Serializable  {
+abstract class jdk3/AllStructures implements java/lang/Runnable java/lang/Cloneable java/io/Serializable {
 
   // compiled from: AllStructures.java
   // access flags 0x2

asm-util/src/test/resources/jdk5.AllStructures$EnumClass.txt

@@ -2,7 +2,7 @@
 // access flags 0x4030
 // signature Ljava/lang/Enum<Ljdk5/AllStructures$EnumClass;>;
 // declaration:  extends java.lang.Enum<jdk5.AllStructures$EnumClass>
-final enum jdk5/AllStructures$EnumClass extends java/lang/Enum  {
+final enum jdk5/AllStructures$EnumClass extends java/lang/Enum {
 
   // compiled from: AllStructures.java
   // access flags 0x4018

asm-util/src/test/resources/jdk5.AllStructures$InvisibleAnnotation.txt

 // class version 49.0 (49)
 // access flags 0x2600
-abstract @interface jdk5/AllStructures$InvisibleAnnotation implements java/lang/annotation/Annotation  {
+abstract @interface jdk5/AllStructures$InvisibleAnnotation implements java/lang/annotation/Annotation {
 
   // compiled from: AllStructures.java
 

asm-util/src/test/resources/jdk5.AllStructures.txt

@@ -3,7 +3,7 @@
 // access flags 0x20020
 // signature <U0:Ljava/lang/Object;U1:Ljava/lang/Number;U2::Ljava/util/List<Ljava/lang/String;>;U3::Ljava/util/List<*>;U4::Ljava/util/List<+Ljava/lang/Number;>;U5::Ljava/util/List<-Ljava/lang/Number;>;U6:Ljava/lang/Number;:Ljava/lang/Runnable;:Ljava/lang/Cloneable;>Ljava/lang/Object;Ljava/util/Comparator<Ljava/lang/Integer;>;
 // declaration: <U0, U1 extends java.lang.Number, U2 extends java.util.List<java.lang.String>, U3 extends java.util.List<?>, U4 extends java.util.List<? extends java.lang.Number>, U5 extends java.util.List<? super java.lang.Number>, U6 extends java.lang.Number extends java.lang.Runnable, java.lang.Cloneable> implements java.util.Comparator<java.lang.Integer>
-class jdk5/AllStructures implements java/util/Comparator  {
+class jdk5/AllStructures implements java/util/Comparator {
 
   // compiled from: AllStructures.java
 

asm-util/src/test/resources/jdk8.AllStructures$1.txt

 // class version 52.0 (52)
 // access flags 0x20
-class jdk8/AllStructures$1 implements java/lang/Runnable  {
+class jdk8/AllStructures$1 implements java/lang/Runnable {
 
   // compiled from: AllStructures.java
   OUTERCLASS jdk8/AllStructures anonymousInnerClass ()Ljava/lang/Runnable;

asm-util/src/test/resources/jdk8.AllStructures.txt

@@ -2,7 +2,7 @@
 // access flags 0x421
 // signature <U0:Ljava/lang/Object;U1::Ljava/util/List<TU0;>;U2::Ljava/util/Collection<TU0;>;>Ljava/util/HashMap<TU0;TU1;>;Ljava/util/concurrent/Callable<TU0;>;Ljava/util/concurrent/Future<TU1;>;
 // declaration: <U0, U1 extends java.util.List<U0>, U2 extends java.util.Collection<U0>> extends java.util.HashMap<U0, U1> implements java.util.concurrent.Callable<U0>, java.util.concurrent.Future<U1>
-public abstract class jdk8/AllStructures extends java/util/HashMap  implements java/util/concurrent/Callable java/util/concurrent/Future  {
+public abstract class jdk8/AllStructures extends java/util/HashMap implements java/util/concurrent/Callable java/util/concurrent/Future {
 
   // compiled from: AllStructures.java