Fix extraction of source <-> class mappings for Java

This was in the original, to-upstream source, but it got lost somewhere.

internal/compiler-bridge/src/main/scala/xsbt/API.scala

@@ -210,7 +210,7 @@ final class API(val global: CallbackGlobal) extends Compat with GlobalHelpers wi
       !ignoredSymbol(sym) &&
       sym.isStatic &&
       !sym.isImplClass &&
-      !sym.hasFlag(Flags.JAVA) &&
+      (!sym.hasFlag(Flags.JAVA) || global.callback.isPickleJava) &&
       !sym.isNestedClass
     }
   }

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/build.json

@@ -0,0 +1,15 @@
+{
+  "projects": [
+    {
+      "name": "use",
+      "dependsOn": [
+        "dep"
+      ],
+      "scalaVersion": "2.13.3"
+    },
+    {
+      "name": "dep",
+      "scalaVersion": "2.13.3"
+    }
+  ]
+}

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/changes/B2.scala

@@ -0,0 +1,6 @@
+package example
+
+object B {
+  val y = A.x + 1
+  def main(args: Array[String]): Unit = println(y)
+}

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/changes/Other.scala

@@ -0,0 +1,5 @@
+package example
+
+object Other {
+  def z = 1
+}

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/dep/A.java

@@ -0,0 +1,5 @@
+package example;
+
+public class A {
+  public static int x() { return 3; }
+}

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/dep/incOptions.properties

@@ -0,0 +1 @@
+pipelining = true

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/test

@@ -0,0 +1,9 @@
+# base-line
+> use/compile
+$ sleep 1000
+
+# 1. make dep recompile something other than A
+# 2. make use recompile, needing a pickle for A
+$ copy-file changes/Other.scala dep/Other.scala
+$ copy-file changes/B2.scala use/B.scala
+> use/compile

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/use/B.scala

@@ -0,0 +1,6 @@
+package example
+
+object B {
+  val y = A.x
+  def main(args: Array[String]): Unit = println(y)
+}

zinc/src/sbt-test/source-dependencies/subproject-pipelining-mixed/use/incOptions.properties

@@ -0,0 +1 @@
+pipelining = true