fix(vm): EIP-150 63/64 + call stipend for precompile outbound Call; add legacy opt-out and tests#277
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lbayas wants to merge 3 commits intoava-labs:mainfrom
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Closes #224
Why this should be merged
Outbound PrecompileEnvironment.Call should match normal CALL semantics on post‑EIP‑150 rulesets: cap transferable gas with the 63/64 rule and apply the call‑value stipend when value is non‑zero. Without that, stateful precompiles can over‑fund nested calls or diverge from what the EVM does for ordinary contracts, which is surprising for integrators and hard to reason about for security. This change aligns behaviour with the spec and with EVM.Call, while keeping an explicit, deprecated escape hatch for legacy deployments.
How this works
When EIP‑150 applies, precompile Call now follows the same outbound gas path as the CALL opcode (63/64 of remaining gas as an upper bound, plus CallStipend when a non‑zero value is transferred). vm.WithLegacyOutboundCallGas() is a CallOption that restores the old behaviour for a single call: parent is charged the full gas argument and the callee receives that full amount (no 63/64 cap, no stipend). New precompiles should rely on the default; the option exists only for backwards compatibility.
How this was tested
go test on core/vm via
go test -count=1 ./core/...(this will include contracts.libevm_test.go cases that cover outbound Call with and without WithLegacyOutboundCallGas)