Hotfix bound threads for workers unsafe calls for llvm

[jberthold]

Fixes a problem with recently-introduced thread-local storage in the LLVM backend.
We have to make sure that all foreign calls relating to an LLVM-based term evaluation use the same OS thread, which can only be achieved via bound threads .

This PR

• adds a flag to the generic RPC server in kore-rpc-types to run request worker threads in bound threads (using forkOS)
• kore-rpc-booster uses this flag for bound threads when an LLVM backend library is used
• declares the LLVM backend calls unsafe to make executing OS threads block instead of having new OS threads created for concurrent Haskell execution (they won't read HS heap data and never call back into Haskell).

This should protect us against problems related to using thread-local storage in the LLVM backend. Needs to be thoroughly tested before merging, because issues only materialised in proofs with substantial workload and parallel exploration.

PR #4080 uses runInBoundThread on the individual request processing calls instead of running the whole worker thread in the server as a bound thread. This was not solving the problem.

[jberthold]

This branch seems to fix the issues reported by @PetarMax for the Lido proof with parallel exploration.
Running standard KEVM and Kontrol performance tests (KEVM with a version using the updated LLVM backend that was rolled back).
Once we are convinced this does not cause issues on larger proofs we can merge this.

[ehildenb]

Approving with a question.

[jberthold]

kevm tests ran without noticeable performance changes (using v0.1.760).
kontrol tests (using v1.0.85 ) with the usual noise:

Test	HOTFIX-bound-threads-for-workers-unsafe-calls-for-llvm time	master-64ad8705f time	(HOTFIX-bound-threads-for-workers-unsafe-calls-for-llvm/master-64ad8705f) time
ExternalLibTest.testSum()	15.9	18.91	0.8408249603384452
StoreTest.testLoadNonExistent()	12.05	14.33	0.8408932309839497
ExpectRevertTest.testFail_ExpectRevert_failAndSuccess()	18.14	21.19	0.8560641812175555
ConstructorTest.run_constructor()	11.53	13.42	0.8591654247391952
BytesTypeTest.test_bytes32(bytes32)	11.96	13.6	0.8794117647058824
AddrTest.test_addr_true()-trace_options1	18.85	21.29	0.8853922029121655
BlockParamsTest.testCoinBase()	12.17	13.64	0.8922287390029325
EmitContractTest.testExpectEmitDoNotCheckData()	15.68	17.49	0.8965122927387079
kontrol/src/tests/integration/test_foundry_prove.py::test_constructor_with_symbolic_args	58.44	65.15	0.8970069071373752
ExpectRevertTest.test_expectRevert_returnValue()	20.86	23.23	0.8979767541971588
ImmutableVarsTest.test_run_deployment(uint256)	144.78	156.61	0.9244620394610816
CounterTest.testSetNumber(uint256)	21.21	22.9	0.9262008733624455
SymbolicStorageTest.testFail_SymbolicStorage1(uint256)	30.18	32.39	0.9317690645260883
AllowChangesTest.testFailAllowChangesToStorage()	15.51	16.54	0.9377267230955261
PrankTestOrigin.test_origin_setup()	27.34	29.0	0.9427586206896552
SetUpDeployTest.test_extcodesize()	40.24	42.32	0.950850661625709
kontrol/src/tests/integration/test_foundry_prove.py::test_foundry_refute_node	7.96	8.35	0.9532934131736527
AssertTest.test_assert_true_branch(uint256)	25.99	27.14	0.9576271186440677
AllowChangesTest.testAllow()	31.13	32.22	0.9661700806952204
AddrTest.test_notBuiltinAddress_symbolic(address)	16.41	15.67	1.0472239948947033
AllowChangesTest.testFailAllowCallsToAddress()	16.44	15.68	1.0484693877551021
])	30.83	29.37	1.0497105890364316
PrankTestMsgSender.test_msgsender_setup()	29.32	27.8	1.0546762589928058
AssertTest.checkFail_assert_false()	17.65	16.48	1.0709951456310678
CoinBaseTest.test_coinbase_setup()	25.39	23.49	1.0808854831843338
BlockParamsTest.testChainId(uint256)	14.03	12.68	1.1064668769716088
BlockParamsTest.testRoll(uint256)	14.17	12.79	1.1078967943706022
ExpectRevertTest.testFail_expectRevert_false()	20.63	18.3	1.1273224043715846
FeeTest.test_fee_setup()	26.56	23.55	1.1278131634819533
kontrol/src/tests/integration/test_foundry_prove.py::test_foundry_xml_report	23.39	20.63	1.1337857489093555
EmitContractTest.testExpectEmitLessTopics()	17.68	15.43	1.1458198314970836
Setup2Test.test_setup()	13.84	12.01	1.1523730224812656
StoreTest.testGasStoreWarmUp()	18.3	15.86	1.153846153846154
ExpectRevertTest.test_expectRevert_true()	18.16	15.55	1.1678456591639872
kontrol/src/tests/integration/test_foundry_prove.py::test_foundry_merge_loop_heads	87.74	59.55	1.4733837111670864
TOTAL	930.46	924.56	1.006381413861729

[jberthold]

Tests with booster-dev without dramatic regression

Test	HOTFIX-bound-threads-for-workers-unsafe-calls-for-llvm time	master-64ad8705f time	(HOTFIX-bound-threads-for-workers-unsafe-calls-for-llvm/master-64ad8705f) time
benchmarks/overflow00-overflow-spec.k	26.95	29.15	0.9245283018867925
mcd-structured/flipper-tau-pass-spec.k	27.86	29.57	0.9421711193777477
mcd-structured/flipper-ttl-pass-spec.k	32.13	33.51	0.9588182632050135
mcd-structured/dsvalue-read-pass-spec.k	33.79	32.57	1.0374577832361067
TOTAL	120.73	124.8	0.9673878205128206

(this is from running make test-prove-rules ... PYTEST_ARGS='... --use-booster-dev')