Fortran: Free type-bound procedure structs

Fortran: Free type-bound procedure structs

compiling gfortran.dg/typebound_proc_31.f90 leaked the type-bound
structs:

56 bytes in 1 blocks are definitely lost.
  at 0x4C2CC05: calloc (vg_replace_malloc.c:711)
  by 0x151EA90: xcalloc (xmalloc.c:162)
  by 0x8E3E4F: gfc_get_typebound_proc(gfc_typebound_proc*) (symbol.c:4945)
  by 0x84C095: match_procedure_in_type (decl.c:10486)
  by 0x84C095: gfc_match_procedure() (decl.c:6696)
...

gcc/fortran/ChangeLog:

2017-12-06  Bernhard Reutner-Fischer  <aldot@gcc.gnu.org>

	* symbol.c (free_tb_tree): Free type-bound procedure struct.
	(gfc_get_typebound_proc): Use explicit memcpy for clarity.