tools/jimage/JImageToolTest.java fails on Linux32 with OOME (also reported in JDK-8150975, with other issues).

This issue reproducible by run jimage command. When trying to do `jimage recreate` on a large dir, OOME happen. Linux32 only.

To reproduce:
jdk/bin/jimage extract --dir $HOME/temp jdk/lib/modules
    now temp contains many data:
    bash-4.1$ ls -l $HOME/temp|wc -l
    95
    bash-4.1$ du -skh $HOME/temp
    261M

bash-4.1$ jdk/bin/jimage recreate --dir $HOME/temp $HOME/temp1
Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
at jdk.tools.jlink.internal.ImageFileCreator.readAllBytes(jdk.jlink@9-ea/ImageFileCreator.java:316)
at jdk.tools.jlink.internal.ImageFileCreator.createPools(jdk.jlink@9-ea/ImageFileCreator.java:284)
at jdk.tools.jlink.internal.ImageFileCreator.recreateJimage(jdk.jlink@9-ea/ImageFileCreator.java:147)
at jdk.tools.jimage.ExtractedImage.recreateJImage(jdk.jlink@9-ea/ExtractedImage.java:72)
at jdk.tools.jimage.JImageTask.recreate(jdk.jlink@9-ea/JImageTask.java:207)
at jdk.tools.jimage.JImageTask.run(jdk.jlink@9-ea/JImageTask.java:378)
at jdk.tools.jimage.JImageTask.run(jdk.jlink@9-ea/JImageTask.java:173)
at jdk.tools.jimage.Main.main(jdk.jlink@9-ea/Main.java:34)

Add "-J-Xms512m -J-Xmx1024m" works though:
bash-4.1$ jdk/bin/jimage -J-Xms512m -J-Xmx1024m recreate --dir $HOME/temp $HOME/temp1
bash-4.1$ jdk/bin/jimage verify $HOME/temp1
jimage: temp1

If delete some data from "temp", say, only keep java.corba, jimage recreate works fine then.