Stop passing the gold plugin path to llvm-ar.

llvm-ar takes a --plugin argument but it is ignored for compatibility,
so passing it has no effect.

Change-Id: I4fc51d226d66cf2a43462d3d4ccc12e6e5ebb226

cc/builder.go

@@ -247,7 +247,6 @@ type builderFlags struct {
 	systemIncludeFlags string
 
 	groupStaticLibs bool
-	arGoldPlugin    bool
 
 	stripKeepSymbols       bool
 	stripKeepMiniDebugInfo bool
@@ -485,9 +484,6 @@ func TransformObjToStaticLib(ctx android.ModuleContext, objFiles android.Paths,
 	if !ctx.Darwin() {
 		arFlags += " -format=gnu"
 	}
-	if flags.arGoldPlugin {
-		arFlags += " --plugin ${config.LLVMGoldPlugin}"
-	}
 	if flags.arFlags != "" {
 		arFlags += " " + flags.arFlags
 	}