Don't hop to the first enclosing, non-silent context when typing refinements.

Closes SI-5305.

This reverts a few lines of e5cfe47a19, which was a remedy for SI-3614 and SI-3856*. I added a test case for the former, the
latter was already tested. Both tests pass after this change, and they do so with the old and new pattern matcher.

But does this change still "avoid trees with null types in presentation compiler"? What was the intent of the context hopping in the first place?

* Based on this comment: https://issues.scala-lang.org/browse/SI-3614?focusedCommentId=50477&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-50477, which elaborates further than the commit comment of e5cfe47a19.
Test for SI-5394.
Address doc comment rot in the standard library.

- Match @param/@tparam names to the actual parameter name
- Use @tparam for type parameters
- Whitespace is required between `*` and `@`
- Fix incorrect references to @define macros.
- Use of monospace `` and {{{}}} (much more needed)
- Remove `@param p1 ...` stubs, which appear in the generated docss.
  - But, retainsed `@param p1` stubs, assuming they will be filtered from
    the generated docs by SI-5795.
- Avoid use of the shorthand `@param   doc for the solitary param`
  (which works, but isn't recognized by the code inspection in IntelliJ
  I used to sweep through the problems)

The remaining warnings from `ant docs` seem spurious, I suspect they are
an unintended consequence of documenting extension methods.

  [scaladoc] /Users/jason/code/scala/src/library/scala/collection/TraversableOnce.scala:181: warning: Variable coll undefined in comment for method reduceOption in class Tuple2Zipped
  [scaladoc]   def reduceOption[A1 >: A](op: (A1, A1) => A1): Option[A1] = reduceLeftOption(op)
  [scaladoc]       ^
Test case closes SI-5137.

virtpatmat strikes again.
Merge commit 'refs/pull/543/head'; commit 'refs/pull/544/head'; commit 'refs/pull/546/head' into develop
Specialize lazy vals (closes SI-5552)

Previously, specialized lazy vals would not work at all when used in
specialized classes, and would just return an uninitialized value.
After this patch, they work in the same way as other specialized fields
do (i.e. a new specialized field is created, and the specialized class
uses that instead of the base class' field).

Note that there are still known problems with specialized lazy vals
(for instance SI-4717) but it seemed to me that this was better than
nothing.
Added test case for commit f7d5f45 (re SI-5552)
Removed an unnecessary self type.
Closes SI-5796.
fix SI-5384

make TreeInfo recognize constructor calls after named arguments transformation.
suspend type vars in SubTypePair's equals

SubTypePair's equals method calls =:= on the involved types,
which mutates the TypeVars contained in them
this is undesirable since we're simply checking whether a subtype test is pending

in addition to making subtyping "more correct" for type vars,
it should avoid the stackoverflow that's been plaguing us
(https://groups.google.com/d/topic/scala-internals/2gHzNjtB4xA/discussion)

SubTypePair's equals method method is only called when subtype checking
hits a recursion threshold (subsametypeRecursions >= LogPendingSubTypesThreshold)
Better fix for SI-5676. Review by @paulp
Merge commit 'refs/pull/547/head'; commit 'refs/pull/548/head'; commit 'refs/pull/549/head'; commit 'refs/pull/550/head'; commit 'refs/pull/551/head' into develop
No-op changes.

Fixed a comment and simplified a mysterious "if (x) y else y" method
thanks to the helpful jibe received in comments.
Debugging output tweaks.

And undeprecated Positional.
New starr with adriaan's fix from 1b198fadd1 .

Since we still fail in locker.comp.
Tweak to avoid value classes in modifier check.
Fixed positions for `AnnotationInfo.original`.
Small documentation fixes & small fix to Scaladoc @see formatting
Missed a straggling doc comment.