Revert "[swift-lang] Fix dependency on sourcekitd module"

This reverts commit 0ab98fc.

Author: benlangmuir

stdlib/tools/swift-lang/CMakeLists.txt

@@ -18,7 +18,6 @@ add_swift_target_library(swiftSwiftLang SHARED
   GYB_SOURCES
     UIDs.swift.gyb
 
-  DEPENDS sourcekitd
   SWIFT_MODULE_DEPENDS_OSX Darwin Foundation
   PRIVATE_LINK_LIBRARIES sourcekitd
   SWIFT_COMPILE_FLAGS -F${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib