common/fdlimit: cap on MacOS file limits, fixes #18994 (#19035)

* common/fdlimit: cap on MacOS file limits, fixes #18994

* common/fdlimit: fix Maximum-check to respect OPEN_MAX

* common/fdlimit: return error if OPEN_MAX is exceeded in Raise()

* common/fdlimit: goimports

* common/fdlimit: check value after setting fdlimit

* common/fdlimit: make comment a bit more descriptive

* cmd/utils: make fdlimit happy path a bit cleaner

(cherry picked from commit f48da43bae)

common/fdlimit/fdlimit_freebsd.go

@@ -26,11 +26,11 @@ import "syscall"
 
 // Raise tries to maximize the file descriptor allowance of this process
 // to the maximum hard-limit allowed by the OS.
-func Raise(max uint64) error {
+func Raise(max uint64) (uint64, error) {
 	// Get the current limit
 	var limit syscall.Rlimit
 	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
-		return err
+		return 0, err
 	}
 	// Try to update the limit to the max allowance
 	limit.Cur = limit.Max
@@ -38,9 +38,12 @@ func Raise(max uint64) error {
 		limit.Cur = int64(max)
 	}
 	if err := syscall.Setrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
-		return err
+		return 0, err
 	}
-	return nil
+	if err := syscall.Getrlimit(syscall.RLIMIT_NOFILE, &limit); err != nil {
+		return 0, err
+	}
+	return limit.Cur, nil
 }
 
 // Current retrieves the number of file descriptors allowed to be opened by this