fix(ci): solve gas meter race condition in integration tests

[almk-dev]

Description

Adds teardowns to integration evmd integration tests and added locks for state reads and commits.
Also adds the count=1 flag to Makefile test targets so that flakes are discovered earlier (locally).

Addresses the following tests:

• TestCheckTxHandlerForCommittedAndLowerNonceTxs race and flake
  • runReorg()/StateAt race
• TestBlockchainRaceCondition nil pointer error

Closes: #722

[vladjdk]

Regarding the TestBlockchainRaceCondition test, are we sure that this race condition only occurs during testing, and not during production. If it occurs in production, is it a problem? If so, what should we do to solve it?

[almk-dev]

@vladjdk There is actually no data race in the TestBlockchainRaceCondition test. It's just a nil pointer error that was introduced because now we call CacheContext() so we need to actually set up the test properly with a multistore.

[signal SIGSEGV: segmentation violation code=0x1 addr=0x18 pc=0x22df70b]

goroutine 43 [running]:
github.com/cosmos/cosmos-sdk/types.Context.CacheContext({{0x0, 0x0}, {0x0, 0x0}, {{0x0, 0x0}, {0x0, 0x0}, 0x1, {0x0, ...}, ...}, ...})
	/home/runner/go/pkg/mod/github.com/cosmos/cosmos-sdk@v0.53.4/types/context.go:357 +0xeb
github.com/cosmos/evm/mempool.(*Blockchain).StateAt(0xc000c70808, {0x12, 0x34, 0x56, 0x78, 0x90, 0xab, 0xcd, 0xef, 0x12, ...})
	/home/runner/work/evm/evm/mempool/blockchain.go:217 +0x538
github.com/cosmos/evm/mempool_test.TestBlockchainRaceCondition.func3()
	/home/runner/work/evm/evm/mempool/blockchain_test.go:99 +0x155
created by github.com/cosmos/evm/mempool_test.TestBlockchainRaceCondition in goroutine 41
	/home/runner/work/evm/evm/mempool/blockchain_test.go:95 +0x1365
FAIL	github.com/cosmos/evm/mempool	0.157s