Use jdk-module-image as boot jdk (modules build + SKIP_BOOT_CYCLE=false)

[Mandy Chung]

Kelly, Alan, Karen,

Jon and I have been discussing the testing for the new javac change and 
modules image.   Building JDK itself is one the the simplest and most 
effective tests that Jon typically uses to validate javac changes (by 
building JDK with SKIP_BOOT_CYCLE=false).

Currently, "make SKIP_BOOT_CYCLE=false all" will first build a legacy 
jdk image and set it as the ALT_BOOTDIR to rebuild the jdk.  As Jon 
suggests, for modules build, SKIP_BOOT_CYCLE=false should use the 
jdk-module-image as the ALT_BOOTDIR to rebuild the jdk modules.

This fix makes changes in the top level repo, jdk, hotspot, and corba 
repository as follows:

1. http://cr.openjdk.java.net/~mchung/jigsaw/bootdir-modules-image/top-repo

   - Set JDK_IMAGE_NAME to j2sdk-image for legacy image build or
     jdk-module-image for modules image build.
   - not to create j2sdk-image for modules build (a bug Jon reported)

2. http://cr.openjdk.java.net/~mchung/jigsaw/bootdir-modules-image/jdk

   - minor cleanup such as using absolute path of the modules directory
   - Add OTHER_JAVAHFLAGS that will be used to set classpath
     to look up pkcs11 and mscapi classes from a temp directory
   - Add the logics to import from the modules instead of rt.jar and 
resources.jar
     Eventually we should import modules instead of copying in the classes.
   - eliminate the second build of the make/modules/Makefile
     Modules.gmk to invoke make/modules/Makefile build was needed
     so as to make sure the jdk modules in the "modules" directory
     are up-to-date.  However, this is only needed for jdk developers who
     is doing incremental builds after the jdk is modularized.  Like the 
images
     build taking the current content from the "classes" directory, it 
will just
     take the current content in the "modules" directory to build the 
modules
     images.  For incremental builds, the jdk developers need to make
     sure the jdk modules are up-to-date.  I'll also come up with some
     better way to make our life easier in updating the jdk-module-image.

3. http://cr.openjdk.java.net/~mchung/jigsaw/bootdir-modules-image/corba/

    - corba, for some reason, links with libjvm.so and libjava.so. 
      The fix is to include the new library path of the jdk-module-image.
      This will need to change when we move the native libraries to
      the module content.

4. http://cr.openjdk.java.net/~mchung/jigsaw/bootdir-modules-image/hotspot/

    - The makefile checks if the tools.jar exists for building SA.  In 
the modular
      world, it no longer has the tools.jar.

An open issue:  the jaxp and jaxws build may download the source bundles.
With using jdk-module-image as the boot jdk, jaxp and jaxws build will
set ANT_JAVA_HOME to the jdk-module-image that will fail the download
as security/crypto support in the modules image is an open issue.

Caused by: java.lang.SecurityException: Can not initialize cryptographic 
mechanism^M
        at javax.crypto.JceSecurity.<clinit>(JceSecurity.java:86)^M

I'd like to push this set of changes in jigsaw althought there is the 
jaxp and jaxws
bundle download issue.  As long as there is a local downloaded copy of the
jaxp/jaxws bundle, it will build fine.

Thanks
Mandy