Changes

Add concurrency control to cancel in-progress PR workflows

ISO8601 DateComponents format style (#1209)

* ISO8601 DateComponents style

* Add Hashable to ISO8601FormatStyle

Add dependencies to SwiftSyntax60[12] (#3034)

Adds missing dependencies to the version marker modules from SwiftSyntax so that they can be found from a `canImport`.

Minor Codable conformance improvements in SwiftBuildSupport (#8449)

### Motivation:
Some of the `SwiftBuildSupport/PIFBuilder.swift` encoding/decoding code
was using unsafe string keys. This replaces with proper typesafe keys.

This part of the ground work to support the new PIF builder in
`SwiftBuildSupport` (i.e., rdar://147527170).

### Modifications:
When conforming to `Codable`, replace string keys with `enum` based keys
instead.

### Result:
The resulting code is a tad safer and easier to understand :-)

Tracked by rdar://148546582.

[CoroutineAccessors] Use async bit in descriptors.

To facilitate back deployment, make use of the fact that the async bit
has up to now never been set for read and modify accessors and claim
that set bit to indicate that it is a callee-allocated coroutine.  This
has the virtue of being completely back deployable because like async
function pointers coro function pointers must be auth'd and signed as
data.

[xcodegen] Print the time taken to generate

Tests: Use `#include` instead of `#import` for compatibility on Windows.

The `#import` directive is not supported by Clang in MSVC compatibility mode,
so use `#include` instead for compatibility in the ClangImporter tests for
custom availability domains.

Resolves rdar://147122406.

[cxx-interop] Switch to non-experimental flag in tests

This gets rid of the flag deprecation warning that was printed for `enable-experimental-cxx-interop`.

add Sendable to the allowed attributes in declaration fragments (#80465)

rdar://142903358

[lldb] Mark swift tests as such

(cherry picked from commit 1d8c3bb8032365df0e563685900f268aad8f6d39)

[lldb] Clear thread-creation breakpoints in ProcessGDBRemote::Clear (#134397)

Currently, these breakpoints are being accumulated every time a new
process if created (e.g. through a `run`). Depending on the
circumstances, the old breakpoints are even left enabled, interfering
with subsequent processes. This is addressed by removing the breakpoints
in ProcessGDBRemote::Clear

Note that these breakpoints are more of a PlatformDarwin thing, so in
the future we should look into moving them there.

(cherry picked from commit 232525f06942adb3b9977632e38dcd5f08c0642d)