tree-optimization/108500 - avoid useless fast-query compute in CFG cleanup

tree-optimization/108500 - avoid useless fast-query compute in CFG cleanup

CFG cleanup computes dominators before the loop over blocks looking
for merging opportunities.  That computes also the fast-query DFS
numbers but that's a bit pointless since any CFG cleanup will invalidate
them immediately (they are re-computed before fixing up loops).
The following avoids this and fixes the SIGSEGV due to the deep
recursion in assign_dfs_numbers after inlining very many small
functions.

	PR tree-optimization/108500
	* dominance.h (calculate_dominance_info): Add parameter
	to indicate fast-query compute, defaulted to true.
	* dominance.cc (calculate_dominance_info): Honor
	fast-query compute parameter.
	* tree-cfgcleanup.cc (cleanup_tree_cfg_noloop): Do
	not compute the dominator fast-query DFS numbers.