Add deprecation warning to lock class
SI-7265 javaSpecVersion, adjust isJava... tests

Make this and related properties public, because they
are useful.

This change ought to have been committed at 2.11 and then
backported with restrictions, rather than vice-versa.

Note that they are defined in the order, version, vendor
and name, which is the order from the underlying javadoc.

It would be a neat feature of the PR validator, as previously
imagined, to run a "pending" test and then, on success and
merge, to move it automatically to the canonical suite.
SI-7737 Regex matches Char

Enables Char extraction by regex.

```
val r = """(\p{Lower})""".r
"cat"(0) match { case r(x) => true }
val nc = """\p{Lower}""".r
"cat"(0) match { case nc() => true }
```
Merge pull request #2780 from lcycon/lcycon-deprecate_lock

Add deprecation warning to scala.concurrent.Lock class
Merge pull request #2791 from som-snytt/issue/7265-2.11

SI-7265 javaSpecVersion, adjust isJava... tests for 2.11
Merge pull request #2819 from som-snytt/issue/regextract-char

SI-7737 Regex matches Char
Crasher in symbol tracer.
Repair NPE in -Ytyper-debug output.
Add some standard names used in pattern matcher.
Some general purpose methods.

Motivated by pattern matcher work, also useful elsewhere.
Expand the understanding of bytecode tests.

The new method is the same as sameMethodAndFieldSignatures, but ignores
generic signatures. This allows for testing methods which receive the same
descriptor but differing generic signatures. In particular, this happens
with value classes, which get a generic signature where a method written
in terms of the underlying values does not.
Add a helper method drop to ScalaRunTime.

We should do a lot more of this - it's ridiculously difficult
and error prone to generate code of this kind involving implicits,
type inference, etc. where the same goal is trivially accomplished
by generating a method call and letting the typer work out the
details.
Tests for name-based pattern matcher.
Pushed some nosiy logging down to debuglog.
Removed some dead code in Uncurry.
Positioned variations of inform/warning/globalError.

Because who doesn't want a little positioning in their life.
Cosmetic cleanup in the matcher.
Cleanups in Unapplies.
Add checkability condition.

All parents of an intersection type must be checkable for the
type to be checkable.
Minor improvement in pattern typer inference.

This exploits the infrastructure developed for checking the
checkability of type patterns to improve pattern type inference,
which suffered from a similar deficit. There was a hack for
SI-2486, the best I could manage at the time I wrote it; that
is replaced with the principled approach.