Preparatory work before subclass renaming

Preparatory work before subclass renaming

Various variables have names that confuse my subclass renaming
script.  Rename them now to simplify the mass-renaming.

gcc/ChangeLog.gimple-classes:
	* tree-inline.h (struct copy_body_data): Rename field
	"gimple_call" to "call_stmt".

	* gimplify.c (gimplify_bind_expr): Rename local "gimple_bind" to
	"bind_stmt".
	(gimplify_switch_expr): Rename local "gimple_switch" to
	"switch_stmt".
	(gimplify_cond_expr): Rename local "gimple_cond" to "cond_stmt".
	* tree-eh.c (lower_catch): Rename local "gcatch" to "catch_stmt".
	* tree-inline.c (copy_bb): Update for renaming of field within
	struct copy_body_data from "gimple_call" to "call_stmt".
	(copy_cfg_body): Likewise.
	(copy_debug_stmt): Likewise.
	(expand_call_inline): Likewise.