[CMake] Fix generated Xcode-project ignoring output directory setting…

… for LLDB.framework

Other generators honor the `LIBRARY_OUTPUT_DIRECTORY` target property, but apparently Xcode doesn't. So we call `set_output_directory()` as `llvm_add_library()` would do and this works.
Note that `LIBRARY_OUTPUT_DIRECTORY` is still necessary, because it's used to store and read the target's absolute build directory (while `LLDB_FRAMEWORK_BUILD_DIR` is relative!).

llvm-svn: 363280

lldb/cmake/modules/LLDBFramework.cmake

@@ -26,6 +26,12 @@ set_target_properties(liblldb PROPERTIES
   MACOSX_FRAMEWORK_INFO_PLIST ${LLDB_SOURCE_DIR}/resources/LLDB-Info.plist.in
 )
 
+# Defined in AddLLVM.cmake; handles edge cases for multi-config generators
+set_output_directory(liblldb
+  BINARY_DIR ${framework_target_dir}
+  LIBRARY_DIR ${framework_target_dir}
+)
+
 # Affects the layout of the framework bundle (default is macOS layout).
 if(IOS)
   set_target_properties(liblldb PROPERTIES