core/evm: RANDOM opcode (EIP-4399) (#24141)

* core: implement eip-4399 random opcode

* core: make vmconfig threadsafe

* core: miner: pass vmConfig by value not reference

* all: enable 4399 by Rules

* core: remove diff (f)

* tests: set proper difficulty (f)

* smaller diff (f)

* eth/catalyst: nit

* core: make RANDOM a pointer which is only set post-merge

* cmd/evm/internal/t8ntool: fix t8n tracing of 4399

* tests: set difficulty

* cmd/evm/internal/t8ntool: check that baserules are london before applying the merge chainrules

core/evm.go

@@ -40,6 +40,7 @@ func NewEVMBlockContext(header *types.Header, chain ChainContext, author *common
 	var (
 		beneficiary common.Address
 		baseFee     *big.Int
+		random      *common.Hash
 	)
 
 	// If we don't have an explicit author (i.e. not mining), extract from the header
@@ -51,6 +52,9 @@ func NewEVMBlockContext(header *types.Header, chain ChainContext, author *common
 	if header.BaseFee != nil {
 		baseFee = new(big.Int).Set(header.BaseFee)
 	}
+	if header.Difficulty.Cmp(common.Big0) == 0 {
+		random = &header.MixDigest
+	}
 	return vm.BlockContext{
 		CanTransfer: CanTransfer,
 		Transfer:    Transfer,
@@ -61,6 +65,7 @@ func NewEVMBlockContext(header *types.Header, chain ChainContext, author *common
 		Difficulty:  new(big.Int).Set(header.Difficulty),
 		BaseFee:     baseFee,
 		GasLimit:    header.GasLimit,
+		Random:      random,
 	}
 }