One minor revision: this lifts the proposed restriction against
overriding a non-open method with an open one. On reflection,
that was inconsistent with the existing rule permitting non-public
methods to be overridden with public ones. The restriction on
subclassing a non-open class with an open class remains, and is
in fact consistent with the existing access rule.
* A bunch of them require objc_interop because they import code containing
Objective-C.
* Many others fail on Ubuntu 14.04 because the C++ there doesn't have a
functional std::regex implementation which is required by the
`complete-test` tool.
It may be possible to adjust some of these tests in the future to not
need these extra requirements, but this is a straightforward way to
clean up Linux test results for now.
The code goes into its own sub-tree under 'tools' but tests go under 'test',
so that running 'check-swift' will also run all the SourceKit tests.
SourceKit is disabled on non-darwin platforms.
