[gn build] Port 10f16bc

Author: llvmgnsyncbot

llvm/utils/gn/secondary/lldb/source/Plugins/ABI/X86/BUILD.gn

@@ -16,6 +16,5 @@ static_library("X86") {
     "ABISysV_x86_64.cpp",
     "ABIWindows_x86_64.cpp",
     "ABIX86.cpp",
-    "ABIX86_i386.cpp",
   ]
 }