Problem: no integration test for block gas limit

[yihuang]

we fixed two issues regarding block gas limit, good to add regression integration test case:

• tx should revert when exceeds block gas limit
• RPC should report correct block gas used when block gas limit is exceeded.

[yihuang]

After the gas meter issue is fixed: #378, it won't include the transactions that exceed the block gas limit in the first place.
So may be difficult to test this scenario in integration tests, closing now.