Use --frontend_file for ninja instead of cat

Ninja now knows how to write directly to a file (or in our case, a named
pipe). This works around an issue we were seeing on Mac, where Go would
just hang after 50-2000 proto messages. It's also just a simpler
solution.

Bug: 111544015
Test: `m` with updated ninja on both Linux & Mac
Change-Id: Ic91920d83a6d2ea0b79e82b467e2423d78189f12

ui/build/ninja.go

@@ -35,7 +35,7 @@ func runNinja(ctx Context, config Config) {
 	executable := config.PrebuiltBuildTool("ninja")
 	args := []string{
 		"-d", "keepdepfile",
-		fmt.Sprintf("--frontend=cat <&3 >%s", fifo),
+		"--frontend_file", fifo,
 	}
 
 	args = append(args, config.NinjaArgs()...)

ui/build/soong.go

@@ -15,7 +15,6 @@
 package build
 
 import (
-	"fmt"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -116,7 +115,7 @@ func runSoong(ctx Context, config Config) {
 			"-d", "keepdepfile",
 			"-w", "dupbuild=err",
 			"-j", strconv.Itoa(config.Parallel()),
-			fmt.Sprintf("--frontend=cat <&3 >%s", fifo),
+			"--frontend_file", fifo,
 			"-f", filepath.Join(config.SoongOutDir(), file))
 		cmd.Sandbox = soongSandbox
 		cmd.RunAndPrintOrFatal()