[SourceKit] Remove an unnecessary link and an include from SourceKitSupport

(cherry picked from commit 79bbbf1)

Author: rintaro

tools/SourceKit/lib/Support/CMakeLists.txt

@@ -7,12 +7,10 @@ add_sourcekit_library(SourceKitSupport
   UIDRegistry.cpp)
 target_link_libraries(SourceKitSupport PRIVATE
   swiftBasic
-  swiftSyntax
   clangBasic
   clangRewrite)
 if(NOT CMAKE_SYSTEM_NAME STREQUAL Darwin)
   target_link_libraries(SourceKitSupport INTERFACE
     dispatch
     BlocksRuntime)
 endif()
-

tools/SourceKit/lib/Support/Tracing.cpp

@@ -12,8 +12,6 @@
 
 #include "SourceKit/Support/Tracing.h"
 
-#include "swift/Frontend/Frontend.h"
-
 #include "llvm/Support/Mutex.h"
 #include "llvm/Support/YAMLTraits.h"