Refactor git command context & pipeline (#36406)

Less and simpler code, fewer bugs

modules/git/error.go

@@ -4,8 +4,6 @@
 package git
 
 import (
-	"context"
-	"errors"
 	"fmt"
 	"strings"
 
@@ -143,10 +141,3 @@ func IsErrMoreThanOne(err error) bool {
 func (err *ErrMoreThanOne) Error() string {
 	return fmt.Sprintf("ErrMoreThanOne Error: %v: %s\n%s", err.Err, err.StdErr, err.StdOut)
 }
-
-func IsErrCanceledOrKilled(err error) bool {
-	// When "cancel()" a git command's context, the returned error of "Run()" could be one of them:
-	// - context.Canceled
-	// - *exec.ExitError: "signal: killed"
-	return err != nil && (errors.Is(err, context.Canceled) || err.Error() == "signal: killed")
-}