unittests: Fix build with LLVM_LINK_LLVM_DYLIB=ON

[aeubanks]

a more specific description would be nice, but lgtm

llvm/unittests/Passes/CMakeLists.txt

 # Needed by LLVM's CMake checks because this file defines multiple targets.
 set(LLVM_OPTIONAL_SOURCES PluginsTest.cpp TestPlugin.cpp DoublerPlugin.cpp PassBuilderBindingsTest.cpp)
 
 # If plugins are disabled, this test will disable itself at runtime. Otherwise,
 # reconfiguring with plugins disabled will leave behind a stale executable.
 if (LLVM_ENABLE_PLUGINS)
   add_definitions(-DLLVM_ENABLE_PLUGINS)
 endif()
 
 # The plugin expects to not link against the Support and Core libraries,
 # but expects them to exist in the process loading the plugin. This doesn't
 # work with DLLs on Windows (where a shared library can't have undefined
 # references), so just skip this testcase on Windows.
 if (NOT WIN32)
-  set(LLVM_LINK_COMPONENTS Support Passes Core)
+  set(LLVM_LINK_COMPONENTS Support Passes Core LLVMAsmParser)
   add_llvm_unittest(PluginsTests
     PluginsTest.cpp
     )
   export_executable_symbols_for_plugins(PluginsTests)
-  target_link_libraries(PluginsTests PRIVATE LLVMAsmParser LLVMTestingSupport)
+  target_link_libraries(PluginsTests PRIVATE LLVMTestingSupport)
 
   set(LLVM_LINK_COMPONENTS)
   foreach(PLUGIN TestPlugin DoublerPlugin)
     add_llvm_library(${PLUGIN} MODULE BUILDTREE_ONLY ${PLUGIN}.cpp)
 
     # Put PLUGIN next to the unit test executable.
     set_output_directory(${PLUGIN}
       BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}