make reconfigure breaks when configured with relative paths

## Symptom
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configure: Rewriting OBJDUMP to "/usr/bin/objdump"
checking for c++filt... c++filt
configure: Rewriting CXXFILT to "/usr/bin/c++filt"
checking for jtreg test harness... /home/fool/fujie/workspace/jtreg/build/images/jtreg
checking for jmh (Java Microbenchmark Harness)... no, error
configure: error: build/jmh/jars does not exist or is not a directory
configure exiting with result code 1
/home/fool/fujie/workspace/jdk-dev/make/Init.gmk:276: recipe for target 'reconfigure' failed
make[1]: *** [reconfigure] Error 1
/home/fool/fujie/workspace/jdk-dev/make/Init.gmk:186: recipe for target 'reconfigure' failed
make: *** [reconfigure] Error 2
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## Reproduce
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#!/bin/bash

JDK=/home/fool/fujie/workspace/jdk-dev
BOOTJDK=/opt/jdk-12

cd ${JDK}
rm build -rf

hg update
bash make/devkit/createJMHBundle.sh
bash configure --with-boot-jdk=${BOOTJDK} --with-jmh=build/jmh/jars

make reconfigure
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## Fix
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diff -r 3326be37cd9a make/autoconf/lib-tests.m4
--- a/make/autoconf/lib-tests.m4 Tue Apr 02 17:27:48 2019 -0700
+++ b/make/autoconf/lib-tests.m4 Wed Apr 03 19:56:24 2019 +0800
@@ -73,6 +73,10 @@
   else
     # Path specified
     JMH_HOME="$with_jmh"
+ if test "x${JMH_HOME:0:1}" != x/; then
+ JMH_HOME="$TOPDIR/$JMH_HOME"
+ fi
+
     if test ! -d [$JMH_HOME]; then
       AC_MSG_RESULT([no, error])
       AC_MSG_ERROR([$JMH_HOME does not exist or is not a directory])
--------------------------------------------------