SI-5756 correctly reifies local module classes

Unlike module classes that are going to be pickled (which are reified
as `<their module reification>.moduleClass), module classes of
local modules need to be reified as symbol defs.

Otherwise we get a stack overflow:
1) Local modules are deemed to be free terms,
2) All free symbols are reified together with their type signature (so that they
   can be a) inspected by anyone interested, b) compiled at runtime),
3) Reifying a type signature of a module involves reifying its module class,
4) Reifying a module class involves reifying a module and calling its module class,
<ad infinitum>

This stack overflow doesn't happen for locatable modules, because they don't need
to have their type signatures reified (these signatures can later be loaded from
pickles if it becomes necessary).

src/compiler/scala/reflect/reify/codegen/GenSymbols.scala

@@ -36,7 +36,8 @@ trait GenSymbols {
     else if (sym.isEmptyPackageClass)
       mirrorMirrorSelect(nme.EmptyPackageClass)
     else if (sym.isModuleClass)
-      Select(Select(reify(sym.sourceModule), nme.asModule), nme.moduleClass)
+      if (sym.sourceModule.isLocatable) Select(Select(reify(sym.sourceModule), nme.asModule), nme.moduleClass)
+      else reifySymDef(sym)
     else if (sym.isPackage)
       mirrorMirrorCall(nme.staticPackage, reify(sym.fullName))
     else if (sym.isLocatable) {

test/files/pos/t5756.scala

@@ -0,0 +1,6 @@
+import scala.reflect.runtime.universe._
+
+object Test extends App {
+  def tagme[T: TypeTag](x: T) = typeTag[T]
+  val foo = tagme{object Bar; Bar}
+}

test/files/pos/t6204-a.scala

@@ -0,0 +1,9 @@
+import scala.reflect.runtime.universe._
+
+object Bish {
+  def m {
+    object Bash {
+      typeOf[Option[_]]
+    }
+  }
+}