scripted-diff: s/WITH_MULTIPROCESS/ENABLE_IPC/ in cmake

Rename WITH_MULTIPROCESS to ENABLE_IPC, because ENABLE_IPC is a more accurate
name for the feature. It controls whether the src/ipc/ directory is built and
whether IPC features like -ipcbind, -ipcconnect, and -ipcfd are available. It
does NOT currently enable multiprocess features which are implemented in #10102
building on top of the IPC features. It will also no longer (as of the next
commit), control whether a find_package call is made so the "WITH_" prefix is
also inappropriate.

-BEGIN VERIFY SCRIPT-
git grep -l WITH_MULTIPROCESS | xargs sed -i s/WITH_MULTIPROCESS/ENABLE_IPC/g
-END VERIFY SCRIPT-

src/test/CMakeLists.txt

@@ -157,7 +157,7 @@ if(ENABLE_WALLET)
   add_subdirectory(${PROJECT_SOURCE_DIR}/src/wallet/test wallet)
 endif()
 
-if(WITH_MULTIPROCESS)
+if(ENABLE_IPC)
   target_link_libraries(bitcoin_ipc_test
     PRIVATE
       core_interface