Removing orphan check/flag files.
Limit bad advice given for erroneous pattern.

Don't suggest "_: <none>" as an alternative when the pattern
type doesn't conform to the expected type.
Restore --show-diff to partest-ack.

Looks like that issue was operator error. However partest
option --show-log really has gone missing.
SI-7801 Fix a nightmarish bug in Symbols#adaptInfos

The compiler-in-residence has always been a sketchy affair;
FSC and REPL offers a bounty of bugs that exploit the menagerie
of time-travel mechanisms in play for symbols' metadata (type, flags,
name and owner.) but are often cleverly masked by optimizations in
the compiler based on reference equality.

The latest: an innocuous change in Erasure:

  https://github.com/scala/scala/commit/d8b96bb8#commitcomment-3995163

means that some `ErasureMap`-s over `MethodType`-s are now true
identities (as `UnitTpe` is always the same object, whereas
`erasedTypeRef(UnitClass)` returns an different `TypeRef` each
time.)

This, in turn, enables `TypeMap#mapOver` to reuse
the existing enclosing type, and so on. On such subtleties hinge
further optimizations, such as whether or not a given phase's
`InfoTransformer` needs to add an entry in a symbols type history.

When the REPL (or FSC / Presentation Compiler) creates a new
`Run`, `Symbol#rawInfo` tries to adapt the entries in the type
history for the new run. For packages, this was taken to be a
no-op; each entry is marked as being valid in the new run and
no further action is taken. This logic lurks in `adaptInfos`.

But, when the namer enters a new symbol in a package, it
*mutates* the Scope of that package classes info `enteringTyper`.
So the later entries in the type history *must* be invalidated
and recomputed.

We have two choices for a fix:

 1) modify `Namers#enterInScope` to blow away the subsequent
    type history for the owning symbol after inserting the
    new member. Something like `owner.setInfo(owner.info)` would
    have the desired effect.
 2) Change `adaptInfos` to be more conservative when it comes
    to package classes, and retain only the oldest entry in the
    type history.

This commit goes for option 2.
add toolbox-based utility methods to quasiquotes' tests
refactor definition tests into separate subsuite
add missing copyTypeDef utility function
rename mkAnnotationCtor into mkAnnotation
merge flagsFromBits and FlagsAsBits into FlagsRepr
use NoMods and NoFlags for reification of empty values
move mkNew from tools.nsc.ast.TreeGen to reflect.internal.TreeGen

This is needed for quasiquotes to implement SyntacticNew combinator.
minor changes to TreeGen.mkTemplate

1. Make superPos parameter optional with default value NoPosition
2. use Option instead of List for local optional constructor variable
reduce amount of clutter on -Yquasiquote-debug
SI-7196 add support for refineStat splicing and extraction
refine block and applied/typeapplied splicing/matching semantics

1. blocks now match single term-level expressions to account for
   automatic block elimination. E.g.

   val q"{ ..$stats }" = q"foo"

   will match into stats = List(q"foo"). This is useful to uniformly
   deal with blocks on term level.

2. blocks in quasiquotes collapse into single expressions

3. Applied and TypeApplied now have constructors too which helps
   to unify matching and extraction in quasiquote reifier

4. TypeApplied now matches AppliedTypeTree too

5. Add Syntactic prefix to Applied and TypeApplied
reify ScalaPackage symbol with the help of ScalaDot
add support for function type splicing and extraction
extract out isHole(name)
first-class early def splicing and extraction support
SI-7803 support for matching of anonymous function literals