Fix mem_stress_1/memleak subtest failures/hangs due to system swapping

If a system has a few Mb of MemFree available but many Gb of SwapFree available,
it is possible currently for tst_buffsize to be set to 1/2Gb. This would cause
most of the journal and receive pools (3 of those each of 1/2Gb) to take a total
of 1-1/2Gb of space and most of it in the swap file. This can slow things down
terribly as was seen in an in-house failure/hang in an armv7l box.

Therefore, avoid the use of swap space and just base calculations on MemFree.

mem_stress/u_inref/memleak.csh

@@ -4,6 +4,9 @@
 # Copyright (c) 2002-2016 Fidelity National Information		#
 # Services, Inc. and/or its subsidiaries. All rights reserved.	#
 #								#
+# Copyright (c) 2018 YottaDB LLC. and/or its subsidiaries.	#
+# All rights reserved.						#
+#								#
 #	This source code contains the intellectual property	#
 #	of its copyright holder(s), and is made available	#
 #	under a license.  If you do not know the terms of	#
@@ -34,23 +37,11 @@ if (($?test_replic) && (! $?gtm_test_replay)) then
 	if (-f /proc/meminfo) then
 		# The meminfo lines of interest are:
 		#	MemFree:          ###### kB
-		#	SwapFree:         ###### kB
 		# The test creates three buffers: two journal pools and a receive pool.
 		# So divide free memory into four pieces, allowing a piece for the rest of the test, and base the cap on that.
 		# awk log() is base e, so divide by log(2) to get base 2.
 		# Subtract 18 so we can add $random(18) back below.
-		set cap = `$tst_awk 'BEGIN {mf=0;sf=0} ($1 == "MemFree:") {mf=$2} ($1 == "SwapFree:") {sf=$2} END { print int(log((mf+sf)*1024/4)/log(2)-18) }' /proc/meminfo`
-	else if (-X svmon) then
-		# This is for AIX, where the svmon output looks like:
-		#	               size       inuse        free         pin     virtual  available   mmode
-		#	memory      7929856     4599144     3330712     2195384     2969212    3848788     Ded
-		# See above section for a description of the math.
-		set cap = `svmon -G -O unit=KB | $tst_awk '($1 == "memory") {print int(log((int($7))*1024/4)/log(2)-18) }'`
-	else if (-x /usr/local/bin/top) then
-		# Currently this covers Solaris, but may be used elsewhere as long as the top format looks like:
-		# 	Memory: ####M phys mem, ####M free mem, ####M total swap, ####M free swap
-		# See above section for a description of the math.
-		set cap = `/usr/local/bin/top | $tst_awk '($1 == "Memory:") {print int(log((int($5)+int($11))*1048576/4)/log(2)-18) }'`
+		set cap = `$tst_awk 'BEGIN {mf=0;sf=0} ($1 == "MemFree:") {mf=$2} END { print int(log((mf)*1024/4)/log(2)-18) }' /proc/meminfo`
 	endif
 	if ($cap > $hardcap) then
 		set cap = $hardcap