[jit] Merger of trunk r216524 into jit branch

[David Malcolm]

I've merged svn trunk into the git dmalcolm/jit branch, specifically
from trunk r216746 aka fddbd0194b01f44c5b5f16379fd5405dcf6d71c0
(2014-10-27) bringing in all changes since r216524 aka
d14cac46135326115f0dc589b0b3d2d249d74cf7 (2014-10-21).

Some #include fixups were needed within gcc/jit to track the
header file flattening on trunk.
    
With this change, jit.sum's # of expected passes remains 4663
    
gcc/jit/ChangeLog.jit:
	* dummy-frontend.c: Drop includes of tree-iterator.h,
	tree-ssa-alias.h, gimple-expr.h, gimple.h, gimple-pretty-print.h.
	* jit-playback.c: Drop includes of debug.h, langhooks.h,
	langhooks-def.h, tree-iterator.h, gimple-expr.h, tree-ssa-alias.h,
	gimple.h, gimple-pretty-print.h, diagnostic-core.h, dumpfile.h.