Merge pull request swiftlang#1533 from modocache/build-presets-xctest

[build-presets] Add corelibs-xctest CI preset

Author: shahmishal

utils/build-presets.ini

@@ -256,6 +256,24 @@ skip-test-osx
 skip-test-ios
 skip-test-watchos
 
+# This preset is used by CI to test swift-corelibs-xctest.
+[preset: buildbot_incremental,tools=RA,stdlib=RA,XCTest]
+# We don't use buildbot_incremental_base_all_platforms because we don't need to
+# build for iOS/tvOS.
+mixin-preset=buildbot_incremental_base
+
+# Build Foundation, then build and test XCTest.
+foundation
+xctest
+
+dash-dash
+
+# This preset is meant to test XCTest, not Swift or Foundation. We don't
+# want stochastic failures in those test suites to prevent XCTest tests from
+# being run.
+skip-test-cmark
+skip-test-swift
+skip-test-foundation
 
 [preset: buildbot_incremental_asan,tools=RDA,stdlib=RDA]
 mixin-preset=buildbot_incremental_base_all_platforms