pallet_revive: Switch to 64bit RISC-V (#6565)

This PR updates pallet_revive to the newest PolkaVM version and adapts
the test fixtures and syscall interface to work under 64bit.

Please note that after this PR no 32bit contracts can be deployed (they
will be rejected at deploy time). Pre-deployed 32bit contracts are now
considered defunct since we changes how parameters are passed for
functions with more than 6 arguments.

## Fixtures

The fixtures are now built for the 64bit target. I also removed the
temporary directory mechanism that triggered a full rebuild every time.
It also makes it easier to find the compiled fixtures since they are now
always in `target/pallet-revive-fixtures`.

## Syscall interface

### Passing pointer

Registers and pointers are now 64bit wide. This allows us to pass u64
arguments in a single register. Before we needed two registers to pass
them. This means that just as before we need one register per pointer we
pass. We keep pointers as `u32` argument by truncating the registe...