[Preset] Add new preset for llbuild, and skip test llbuild and cmark for swiftpm preset

Author: shahmishal

utils/build-presets.ini

@@ -1114,9 +1114,31 @@ swiftpm
 
 dash-dash
 
-# Only run watchOS tests
 skip-test-swift
+skip-test-cmark
+skip-test-llbuild
+
+#===------------------------------------------------------------------------===#
+# Test llbuild on macOS builder
+#===------------------------------------------------------------------------===#
+
+[preset: buildbot_llbuild_macos_platform,tools=RA,stdlib=RA]
+mixin-preset=buildbot_incremental_base
+
+build-subdir=buildbot_incremental
+
+# Build Release without debug info, because it is faster to build.
+release
+assertions
 
+# Build llbuild & swiftpm here
+llbuild
+swiftpm
+
+dash-dash
+
+skip-test-swift
+skip-test-cmark
 
 #===------------------------------------------------------------------------===#
 # Remote Mirror Library