Fix the jit build after header flattening of r219402

Fix the jit build after header flattening of r219402

gcc/jit/ChangeLog:
	* dummy-frontend.c: Include "fixed-value.h", "alias.h", "flags.h",
	"symtab.h", "inchash.h".  Move include of "hash-set.h" much
	earlier.
	* jit-builtins.c: Remove redundant includes of "opts.h" and
	"tree.h".
	* jit-common.h: Include "hash-set.h", "input.h", "vec.h",
	"double-int.h", "alias.h", "flags.h", "symtab.h", "inchash.h".
	* jit-playback.c: Include "hashtab.h", "machmode.h", "input.h",
	"statistics.h", "vec.h", "double-int.h", "real.h",
	"fixed-value.h", "alias.h", "flags.h", "symtab.h", "tree-core.h",
	"inchash.h", "fold-const.h".  Move include of "hash-set.h" to
	earlier.
	* jit-recording.c: Remove redundant includes of "opts.h" and
	"tree.h".

From-SVN: r219411