Add Synchronization to abi checker

Author: Azoy

test/abi/Inputs/macOS/arm64/synchronization/baseline

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+// RUN: %empty-directory(%t)
+// RUN: %llvm-nm -g --defined-only -f just-symbols %stdlib_dir/arm64/libswiftSynchronization.dylib > %t/symbols
+// RUN: %abi-symbol-checker %s %t/symbols --base %S/synchronization.swift
+// RUN: diff -u %S/../../Inputs/macOS/arm64/synchronization/baseline-asserts %t/symbols
+
+// REQUIRES: swift_stdlib_asserts
+// REQUIRES: STDLIB_VARIANT=macosx-arm64
+
+// *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment below.)
+
+// Welcome, Build Wrangler!
+//
+// This file lists APIs that have recently changed in a way that potentially
+// indicates an ABI- or source-breaking problem.
+//
+// A failure in this test indicates that there is a potential breaking change in
+// the Standard Library. If you observe a failure outside of a PR test, please
+// reach out to the Standard Library team directly to make sure this gets
+// resolved quickly! If your own PR fails in this test, you probably have an
+// ABI- or source-breaking change in your commits. Please go and fix it.
+//
+// Please DO NOT DISABLE THIS TEST. In addition to ignoring the current set of
+// ABI breaks, XFAILing this test also silences any future ABI breaks that may
+// land on this branch, which simply generates extra work for the next person
+// that picks up the mess.
+//
+// Instead of disabling this test, you'll need to extend the list of expected
+// changes at the bottom. (You'll also need to do this if your own PR triggers
+// false positives, or if you have special permission to break things.) You can
+// find a diff of what needs to be added in the output of the failed test run.
+// The order of lines doesn't matter, and you can also include comments to refer
+// to any bugs you filed.
+//
+// Thank you for your help ensuring the stdlib remains compatible with its past!
+//                                            -- Your friendly stdlib engineers
+
+// *** NOTE: ***
+// You will normally add new entries in 'abi/macOS/arm64/synchronization.swift'
+// instead of this file. This file is dedicated for assert only symbols.
+
+//===----------------------------------------------------------------------===//
+// Synchronization Symbols
+//===----------------------------------------------------------------------===//

test/abi/Inputs/macOS/arm64/synchronization/baseline-asserts

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+// RUN: %empty-directory(%t)
+// RUN: %llvm-nm -g --defined-only -f just-symbols %stdlib_dir/x86_64/libswiftSynchronization.dylib > %t/symbols
+// RUN: %abi-symbol-checker %s %t/symbols --base %S/synchronization.swift
+// RUN: diff -u %S/../../Inputs/macOS/x86_64/synchronization/baseline-asserts %t/symbols
+
+// REQUIRES: swift_stdlib_asserts
+// REQUIRES: STDLIB_VARIANT=macosx-x86_64
+
+// *** DO NOT DISABLE OR XFAIL THIS TEST. *** (See comment below.)
+
+// Welcome, Build Wrangler!
+//
+// This file lists APIs that have recently changed in a way that potentially
+// indicates an ABI- or source-breaking problem.
+//
+// A failure in this test indicates that there is a potential breaking change in
+// the Standard Library. If you observe a failure outside of a PR test, please
+// reach out to the Standard Library team directly to make sure this gets
+// resolved quickly! If your own PR fails in this test, you probably have an
+// ABI- or source-breaking change in your commits. Please go and fix it.
+//
+// Please DO NOT DISABLE THIS TEST. In addition to ignoring the current set of
+// ABI breaks, XFAILing this test also silences any future ABI breaks that may
+// land on this branch, which simply generates extra work for the next person
+// that picks up the mess.
+//
+// Instead of disabling this test, you'll need to extend the list of expected
+// changes at the bottom. (You'll also need to do this if your own PR triggers
+// false positives, or if you have special permission to break things.) You can
+// find a diff of what needs to be added in the output of the failed test run.
+// The order of lines doesn't matter, and you can also include comments to refer
+// to any bugs you filed.
+//
+// Thank you for your help ensuring the stdlib remains compatible with its past!
+//                                            -- Your friendly stdlib engineers
+
+// *** NOTE: ***
+// You will normally add new entries in 'abi/macOS/x86_64/stdlib.swift' instead
+// of this file. This file is dedicated for assert only symbols.
+
+//===----------------------------------------------------------------------===//
+// Synchronization Symbols
+//===----------------------------------------------------------------------===//