Do not add source dependencies on itself.

Adding source dependency on itself doesn't really bring any value so
there's no reason to do it. We avoided recording that kind of dependencies
by performing a check in `AnalysisCallback` implementation. However, if we
have another implementation like `TestCallback` used for testing we do
not benefit from that check.

Therefore, the check has been moved to dependency phase were dependencies
are collected.

compile/inc/src/main/scala/sbt/inc/Compile.scala

@@ -97,7 +97,7 @@ private final class AnalysisCallback(internalMap: File => Option[File], external
 	}
 
 	def sourceDependency(dependsOn: File, source: File, inherited: Boolean) =
-		if(source != dependsOn) {
+		{
 			add(sourceDeps, source, dependsOn)
 			if(inherited) add(inheritedSourceDeps, source, dependsOn)
 		}

compile/interface/src/main/scala/xsbt/Dependency.scala

@@ -79,7 +79,7 @@ final class Dependency(val global: CallbackGlobal) extends LocateClassFile
 							case None => ()
 						}
 					}
-					else
+					else if (onSource.file != sourceFile)
 						callback.sourceDependency(onSource.file, sourceFile, inherited)
 				}
 			}