Function deduplication

[vaivaswatha]

This optimisation pass looks for identical functions and eliminates all but one, replacing calls appropriately.

Ideally this must be run before any other pass, to reduce compile times for all the remaining passes. However, when run before inlining, it impacts some inlining decisions. For example, functions which previously had only a single caller now may have multiple callers, thus preventing them from being inlined. While theoretically that could be good, numbers indicated otherwise. The inliner needs to be tuned before we move dedup ahead of it.

Also, the PR has a minor edit to the order in which inlining is performed on inlining candidates. We now follow lexical order rather than relying on an arbitrary order set by FxHashMap. This was necessary so that equal functions remain equal after inlining. Changing the order of inlining resulted in differences in the order and names of local variables, rendering functions
that were equal before inlining to not be anymore.

Closes #5166

Code size impact on sdk-harness contracts/scripts:

test	before	after	reduction
methods_abi	28	28	0
vec_in_abi	7892	7892	0
type_aliases	172	172	0
tx_predicate	36	36	0
tx_output_predicate	828	828	0
tx_contract	7480	7480	0
token_ops	14332	8512	40.608428691041
test_script_bytes	1140	1140	0
test_script	1620	1620	0
test_contract	6332	5140	18.8250157927985
svec_u8	35800	23640	33.9664804469274
svec_u64	34872	23640	32.2092222986924
svec_u32	35800	23640	33.9664804469274
svec_u16	35800	23640	33.9664804469274
svec_tuple	37192	25048	32.6521832652183
svec_struct	37048	24904	32.7790973871734
svec_str	37040	24896	32.7861771058315
svec_enum	37048	24904	32.7790973871734
svec_bool	35800	23640	33.9664804469274
svec_b256	37040	24896	32.7861771058315
svec_array	37768	25624	32.1542046176657
superabi_supertrait	124	124	0
superabi	124	124	0
storage_vec_to_vec	13308	8720	34.4755034565675
storage_vec_nested	51948	47968	7.66150766150766
storage_string	4620	3436	25.6277056277056
storage_map_nested	74848	57828	22.739418554938
storage_map	120600	40824	66.1492537313433
storage_init	19296	17764	7.93946932006634
storage_bytes	7140	5216	26.9467787114846
storage_access	38388	30712	19.995832030843
storage	16152	12328	23.6750866765726
script_data	392	392	0
script_bytecode	624	624	0
result_in_abi	516	516	0
registers	540	540	0
predicatepredicate_data_struct	388	388	0
predicatepredicate_data_simple	364	364	0
pow	228	228	0
parsing_logs_test_abi	28	28	0
parsing_logs	1244	1244	0
option_in_abi	516	516	0
option_field_order	2672	1804	32.4850299401198
methods_contract	4224	3984	5.68181818181818
messages	876	876	0
logging	400	400	0
hashing	18020	16836	6.57047724750278
generics_in_abi	2584	1732	32.9721362229102
evm_ec_recover	2088	2088	0
evm_test_abi	28	28	0
evm	224	224	0
ec_recover_and_match_predicate	4924	4924	0
ec_recover	2056	2048	0.389105058365759
contract_bytecode	168	168	0
context_testing_abi	28	28	0
context_caller_contract	8200	2568	68.6829268292683
context	404	404	0
configurables_in_script	252	252	0
configurables_in_contract	284	284	0
call_frames_test_abi	28	28	0
call_frames	1196	1196	0
block_test_abi	28	28	0
block	484	484	0
balance_contract	84	84	0
auth_testing_abi	28	28	0
auth_testing_contract	3012	2900	3.71845949535193
auth_caller_script	264	264	0
auth_caller_contract	176	176	0
abi_impl_methods_callable	116	116	0

[vaivaswatha]

There's a unit test ICE'ing. Changing this to Draft.

[vaivaswatha]

This PR, now, also modifies the IR infrstructure to not store AsmBlock in the arena. Details are in this commit message.