Forced inlining of some GC-related methods.

The selection of methods were driven by GCC's -Winline plus some benchmarking.
On ia32, the additional amount of code is roughly 63kB (= 0.07% of Chrome ;-).

BUG=v8:1607

Review URL: https://codereview.chromium.org/12338002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13710 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Prepare push to trunk.  Now working on version 3.17.4.

R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/12338003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13711 ce2b1a6d-e550-0410-aec6-3dcde31c8c00