One Zone per CompilationInfo.

One Zone per CompilationInfo.

The CompilationInfo record now saves a Zone, and the compiler pipeline
allocates memory from the Zone in the CompilationInfo.  Before
compiling a function, we create a Zone on the stack and save a pointer
to that Zone to the CompilationInfo; which then gets picked up and
allocated from.

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/10534139

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11877 ce2b1a6d-e550-0410-aec6-3dcde31c8c00