Update to PolkaVM `0.19`. This version renumbers the opcodes in order to
be in-line with the grey paper. Hopefully, for the last time. This means
that it breaks existing contracts.

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Signed-off-by: xermicus <cyrill@parity.io>
Co-authored-by: command-bot <>
Co-authored-by: xermicus <cyrill@parity.io>