Fix test: only thing wrong should be block number

The old test implementation was finding other problems, like a
base_fee_per_gas that did not match the parent.

Author: carver

tests/core/tester/test_generate_vm_configuration.py

@@ -33,7 +33,7 @@ class CustomFrontierVM(FrontierVM):
         (
             (),
             {},
-            ((0, Forks.Berlin),),
+            ((0, Forks.London),),
         ),
         (
             ((0, 'tangerine-whistle'), (1, 'spurious-dragon')),

tests/core/vm/test_vm.py

@@ -115,10 +115,9 @@ def test_validate_header_succeeds_but_pow_fails(pow_consensus_chain, noproof_con
 
 def test_validate_header_fails_on_invalid_parent(noproof_consensus_chain):
     block1 = noproof_consensus_chain.mine_block()
-    noproof_consensus_chain.mine_block()
-    block3 = noproof_consensus_chain.mine_block()
+    block2 = noproof_consensus_chain.mine_block()
 
-    vm = noproof_consensus_chain.get_vm(block3.header)
+    vm = noproof_consensus_chain.get_vm(block2.header)
 
     with pytest.raises(ValidationError, match="Blocks must be numbered consecutively"):
-        vm.validate_header(block3.header, block1.header)
+        vm.validate_header(block2.header.copy(block_number=3), block1.header)