When max gas = -1, the SDK doesn't allow for infinite gas

[ValarDragon]

See:

cosmos-sdk/baseapp/baseapp.go

Line 535 in 19f0f92

if maxGas := app.getMaximumBlockGas(); maxGas > 0 {

The semantics of max_gas < 0 is for it to allow for infinite gas. However, in getMaximumBlockGas,

cosmos-sdk/baseapp/baseapp.go

Line 291 in 19f0f92

func (app *BaseApp) getMaximumBlockGas() (maxGas uint64) {

the SDK currently does uint64(max_gas). For negative values of gas this yields something on the order of 2**64 - 1, which then yields a gas meter with around 2**64 gas. This is far off from the desired infinity 😜

[alexanderbez]

imho, we simply need to check for overflow here.