torture: Explain and simplify odd "for" loop in mkinitrd.sh

cat > $T/init << '__EOF___'

#!/bin/sh

# Run in userspace a few milliseconds every second.  This helps to

# exercise the NO_HZ_FULL portions of RCU.

# exercise the NO_HZ_FULL portions of RCU.  The 192 instances of "a" was

# empirically shown to give a nice multi-millisecond burst of user-mode

# execution on a 2GHz CPU, as desired.  Modern CPUs will vary from a

# couple of milliseconds up to perhaps 100 milliseconds, which is an

# acceptable range.

#

# Why not calibrate an exact delay?  Because within this initrd, we

# are restricted to Bourne-shell builtins, which as far as I know do not

# provide any means of obtaining a fine-grained timestamp.

a4="a a a a"

a16="$a4 $a4 $a4 $a4"

a64="$a16 $a16 $a16 $a16"

a192="$a64 $a64 $a64"

while :

do

	q=

	for i in \

		a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \

		a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \

		a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \

		a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \

		a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a \

		a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a a

	for i in $a192

	do

		q="$q $i"

	done