WIP: enable integer overflow checks for release builds

[ryankurte]

integer overflow checks would be nice to have, however, these cause summary and ring operations to fail with what is either a mishandled panic or a stack related regression, resulting in an extremely cursed series of observations:

• fault only exists in hw, this is not reproducible in speculos or local tests using -exactly the same- mnemonics and test vectors
  (if an integer overflow panic was the cause i would expect to see the same fault in speculos?)
• USB transport reports zero length response / missing HID header
  (something has gone wrong at the OS level when attempting to respond, for example, attempting to panic while exceeding the stack pointer limitation?)
• app continues to run and respond to user inputs following this failure
  (a panic should result in an abort, but this could be a failure of the nanos_sdk panic handler?)

reproduce by:

• configuring a nanosplus with the test mnemonic (duck diamond ...) to match the test vectors
• building and loading the firmware from this branch with make nanosplus-load
• running the transaction test with cargo run --bin ledger-mob-tests -- --target hid tx --input tests/vectors/tx3.json