IDEA-172368 'Join lines' could handle increment with 0 nicer

java/java-tests/testData/codeInsight/joinLines/AssignmentExpression2.java

@@ -0,0 +1,6 @@
+class Foo {
+    {
+        int <caret>x = 1;
+        x += 2;
+    }
+}

java/java-tests/testData/codeInsight/joinLines/AssignmentExpression2_after.java

@@ -0,0 +1,5 @@
+class Foo {
+    {
+        int x = 1 + 2;
+    }
+}

java/java-tests/testData/codeInsight/joinLines/AssignmentExpression_after.java

@@ -1,5 +1,5 @@
 class Foo {
     {
-        int x = 0 + 2;<caret>
+        int x = 2;
     }
 }