[Syntax] Do not depend on llvm targets for Syntax tests. NFC

They are not required and only slow down the build.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@362530 91177308-0d34-0410-b5e6-96231b3b80d8

unittests/Tooling/Syntax/CMakeLists.txt

@@ -1,5 +1,4 @@
 set(LLVM_LINK_COMPONENTS
-  ${LLVM_TARGETS_TO_BUILD}
   Support
   )