Stop profiling metrics in the same step as other profiles in runsc.

This is part of a series of changes to add metric charts in performance
benchmarks.

This change stops profiling metrics whenever we also stop CPU/heap/mutex
profiles, rather than at `runsc boot` exit. This helps flushing the metrics
data at the right time.

PiperOrigin-RevId: 633287428

runsc/boot/BUILD

@@ -50,6 +50,7 @@ go_library(
         "//pkg/hostos",
         "//pkg/log",
         "//pkg/memutil",
+        "//pkg/metric",
         "//pkg/rand",
         "//pkg/refs",
         "//pkg/sentry/arch",

runsc/boot/loader.go

@@ -36,6 +36,7 @@ import (
 	"gvisor.dev/gvisor/pkg/fd"
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/memutil"
+	"gvisor.dev/gvisor/pkg/metric"
 	"gvisor.dev/gvisor/pkg/rand"
 	"gvisor.dev/gvisor/pkg/refs"
 	"gvisor.dev/gvisor/pkg/sentry/control"
@@ -372,7 +373,11 @@ func getRootCredentials(spec *specs.Spec, conf *config.Config, userNs *auth.User
 // New initializes a new kernel loader configured by spec.
 // New also handles setting up a kernel for restoring a container.
 func New(args Args) (*Loader, error) {
-	stopProfiling := profile.Start(args.ProfileOpts)
+	stopProfilingRuntime := profile.Start(args.ProfileOpts)
+	stopProfiling := func() {
+		stopProfilingRuntime()
+		metric.StopProfilingMetrics()
+	}
 
 	// Initialize seccheck points.
 	seccheck.Initialize()