Fix process locking and state management

There were races with the way process states.  This displayed in ways,
especially around pausing the container for atomic operations.  Users
would get errors like, cannnot delete container in paused state and
such.

This can be eaisly reproduced with `docker` and the following command:

```bash
> (for i in `seq 1 25`; do id=$(docker create  alpine usleep 50000);docker start $id;docker commit $id;docker wait $id;docker rm $id; done)
```

This two issues that this fixes are:

* locks must be held by the owning process, not the state operations.
* If a container ends up being paused but before the operation
completes, the process exists, make sure we resume the container before
setting the the process as exited.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

runtime/v1/linux/proc/exec.go

@@ -41,7 +41,7 @@ import (
 type execProcess struct {
 	wg sync.WaitGroup
 
-	proc.State
+	execState execState
 
 	mu      sync.Mutex
 	id      string
@@ -86,6 +86,13 @@ func (e *execProcess) ExitedAt() time.Time {
 	return e.exited
 }
 
+func (e *execProcess) SetExited(status int) {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	e.execState.SetExited(status)
+}
+
 func (e *execProcess) setExited(status int) {
 	e.status = status
 	e.exited = time.Now()
@@ -93,6 +100,13 @@ func (e *execProcess) setExited(status int) {
 	close(e.waitBlock)
 }
 
+func (e *execProcess) Delete(ctx context.Context) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	return e.execState.Delete(ctx)
+}
+
 func (e *execProcess) delete(ctx context.Context) error {
 	e.wg.Wait()
 	if e.io != nil {
@@ -107,6 +121,13 @@ func (e *execProcess) delete(ctx context.Context) error {
 	return nil
 }
 
+func (e *execProcess) Resize(ws console.WinSize) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	return e.execState.Resize(ws)
+}
+
 func (e *execProcess) resize(ws console.WinSize) error {
 	if e.console == nil {
 		return nil
@@ -114,6 +135,13 @@ func (e *execProcess) resize(ws console.WinSize) error {
 	return e.console.Resize(ws)
 }
 
+func (e *execProcess) Kill(ctx context.Context, sig uint32, _ bool) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	return e.execState.Kill(ctx, sig, false)
+}
+
 func (e *execProcess) kill(ctx context.Context, sig uint32, _ bool) error {
 	pid := e.pid
 	if pid != 0 {
@@ -132,6 +160,13 @@ func (e *execProcess) Stdio() proc.Stdio {
 	return e.stdio
 }
 
+func (e *execProcess) Start(ctx context.Context) error {
+	e.mu.Lock()
+	defer e.mu.Unlock()
+
+	return e.execState.Start(ctx)
+}
+
 func (e *execProcess) start(ctx context.Context) (err error) {
 	var (
 		socket  *runc.Socket