SI-3995 Exclude companions with an existential prefix.

In `(qual: Q).apply(expr)` where `expr` must be implictily
converted to a path dependent type `T` defined in `qual`,
we were looking for companion implicits via a path prefixed
by an existential skolem `_1`. These aren't much good to us,
as when we try to feed them into `mkAttributedQualifer`, a
crash rightly ensues.

This commit excludes companions prefixed by an existentially
bound path.
Expand test with a stably qualified example.

In the example below, we need a view from
`String => l.F0`, and the companion object `FO` is
reachable by a stable, non existentially-bound path.

    class Lift {
      def apply(f: F0) {}

      class F0
      object F0 {
        implicit def f2f0(fn: String): F0 = ???
      }
    }

    object Test {
      val l = new Lift
      l.apply("") // okay
    }

Followup for SI-3995
SI-6548 reflection now correctly enters jinners

When completing Java classes, runtime reflection enumerates their
fields, methods, constructors and inner classes, loads them and
enters them into either the instance part (ClassSymbol) or the
static part (ModuleSymbol).

However unlike fields, methods and constructors, inner classes don't
need to be entered explicitly - they are entered implicitly when
being loaded.

This patch fixes the double-enter problem, make sure that enter-on-load
uses the correct owner, and also hardens jclassAsScala against double
enters that can occur in a different scenario.

Since the fix is about Java-compiled classes, the test needs *.class
artifacts produced by javac. Therefore I updated javac-artifacts.jar to
include the new artifacts along with their source code.
cosmetic renamings in runtime reflection

initClassModule => initClassAndModule
createClassModule => initAndEnterClassAndModule
SI-6795 Adds negative check for "abstract override" on types in traits

"abstract override" shouldn't was being allowed on types in traits but the result
made no sense and the spec says that shouldn't be allowed.
SI-6795 Simplify errors related to "abstract override" on type members

Instead of saying "only allowed on non-type members of traits" use
separate errors for "not allowed on types" and "only allowed on members
of traits"
fixes incorrect handling of Annotated in lazy copier
Cleanup MemberLookup. Better explain ambiguous link targets.
Remove dead code from `Global`.

This is clearly dead-code (`phaseTimings` is not referred
anywhere else in `Global.scala`) and it's safe to remove it since
`phaseTimings` is private.

This dead-code is leftover from 317a1056.

Review by @paulp.
Deprecate `scala.tools.nsc.Phases` because it's dead-code.

The 0a2022c made `scala.tools.nsc.Phases` dead-code. It's not private
so it got deprecated instead of being removing right away.

Review by @paulp.
Merge pull request #1759 from scalamacros/topic/annotated

fixes incorrect handling of Annotated in lazy copier
Merge pull request #1727 from scalamacros/ticket/6548

SI-6548 reflection now correctly enters jinners
Merge pull request #1709 from retronym/ticket/3995

SI-3995 Exclude companions with an existential prefix.
Merge pull request #1772 from gkossakowski/global-deadcode

Remove dead code from `Global`.
Merge pull request #1771 from vigdorchik/si_6605

Cleanup MemberLookup. Better explain ambiguous link targets.
Merge pull request #1778 from JamesIry/p_SI-6795_2.10.x

SI-6795 simplify "abstract override" errors on type members
Work in progress
Add test cases
Don't reify packages as Select

BUILD FAILED
/opt/git-repos/scala/build.xml:2588: java.lang.RuntimeException: Test
suite finished with 10 cases failing:
/opt/git-repos/scala/test/files/run/t5225_2.scala [FAILED]
/opt/git-repos/scala/test/files/run/t6223.scala [FAILED]
/opt/git-repos/scala/test/files/run/t6591_6.scala [FAILED]
/opt/git-repos/scala/test/files/run/freetypes_false_alarm1.scala [FAILED]
/opt/git-repos/scala/test/files/run/reify_ann2a.scala [FAILED]
/opt/git-repos/scala/test/files/run/t6591_4.scala [FAILED]
/opt/git-repos/scala/test/files/run/reify_newimpl_30.scala [FAILED]
/opt/git-repos/scala/test/files/run/t6591_5.scala [FAILED]
/opt/git-repos/scala/test/files/instrumented/inline-in-constructors [FAILED]
/opt/git-repos/scala/test/files/instrumented/InstrumentationTest.scala [FAILED]
Removed redundant case Select(qual, name) if qual.isType