Add 32-bit support to the Mac OS X port

Currently, Oracle supports only a 64-bit port of Java SE on Mac OS X. It would
be useful to have a 32-bit port to use with 32-bit native applications and, to
some extent, in footprint constrained environments.

Note, however, that the 64-bit JVM running with compressed pointers enabled
has only a slightly larger memory footprint than a 32-bit JVM, and generally runs
faster than the 32-bit JVM due to the extra registers present in 64-bit mode.

Note also that compressed pointers are currently not enabled in the 64-bit
OS X JVM due to

7129710: MAC: 64-bit server VM crashes on Mac OS X with Compressed OOPs