Moved the global-pool-allocator to TCompiler so that all memory allocated by the compiler can be de-allocated. Earlier the global-pool-allocator kept accumulating memory from all compilers (symbol-table in particular). The memory was only de-allocated when gpu-process exited or ShFinalize() was called. This was a problem for Chromium which keeps the GPU process around for the browser session. Now the memory is de-allocated as soon as the compiler is deleted, which happens when a tab is closed.
BUG=58808 (crbug.com)
Review URL: http://codereview.appspot.com/3280041

git-svn-id: https://angleproject.googlecode.com/svn/trunk@489 736b8ea6-26fd-11df-bfd4-992fa37f6226