Move size time tables from GGC to heap

this patch moves size time tables out of ggc allocated memory.  This makes
sources bit cleaner and saves about 60MB of GGC memory that turns to about 45MB
of heap memory for cc1plus LTO build.

	* ipa-fnsummary.h (class size_time_entry): Do not GTY annotate.
	(class ipa_fnsummary): Turn size_time_table to auto_vec and
	call_size_time_table to effecient vec; update constructors.
	* ipa-fnsummary.c (ipa_fn_summary::account_size_time): Update.
	(ipa_fn_summary::~ipa_fn_summary): Update.
	(ipa_fn_summary_t::duplicate): Update.
	(ipa_dump_fn_summary): Update.
	(set_switch_stmt_execution_predicate): Update.
	(analyze_function_body): Update.
	(estimate_calls_size_and_time): Update.
	(ipa_call_context::estimate_size_and_time): Update.
	(ipa_merge_fn_summary_after_inlining): Update.
	(ipa_update_overall_fn_summary): Update.
	(inline_read_section): Update.
	(ipa_fn_summary_write): Update.