Merge #20406: util: Avoid invalid integer negation in FormatMoney and ValueFromAmount

1f05dbd06d896849d16b026bfc3315ee8b73a89f util: Avoid invalid integer negation in ValueFromAmount: make ValueFromAmount(const CAmount& n) well-defined also when n is std::numeric_limits<CAmount>::min() (practicalswift)
7cc75c9ba38e516067e5a4ab84311c62ddddced7 util: Avoid invalid integer negation in FormatMoney: make FormatMoney(const CAmount& n) well-defined also when n is std::numeric_limits<CAmount>::min() (practicalswift)

Pull request description:

  Avoid invalid integer negation in `FormatMoney` and `ValueFromAmount`.

  Fixes #20402.

  Before this patch:

  ```
  $ CC=clang CXX=clang++ ./configure --with-sanitizers=undefined
  $ make -C src/ test/test_bitcoin
  $ src/test/test_bitcoin -t rpc_tests/rpc_format_monetary_values -t util_tests/util_FormatMoney
  core_write.cpp:21:29: runtime error: negation of -9223372036854775808 cannot be represented in type 'CAmount'
    (aka 'long'); cast to an unsigned type to negate this value to itself
  SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior core_write.cpp:21:29 in
  test/rpc_tests.cpp(186): error: in "rpc_tests/rpc_format_monetary_values":
    check ValueFromAmount(std::numeric_limits<CAmount>::min()).write() == "-92233720368.54775808" has failed
    [--92233720368.-54775808 != -92233720368.54775808]
  util/moneystr.cpp:16:34: runtime error: negation of -9223372036854775808 cannot be represented in type 'CAmount'
    (aka 'long'); cast to an unsigned type to negate this value to itself
  SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior util/moneystr.cpp:16:34 in
  test/util_tests.cpp(1188): error: in "util_tests/util_FormatMoney":
    check FormatMoney(std::numeric_limits<CAmount>::min()) == "-92233720368.54775808" has failed
    [--92233720368.-54775808 != -92233720368.54775808]
  ```

  After this patch:

  ```
  $ CC=clang CXX=clang++ ./configure --with-sanitizers=undefined
  $ make -C src/ test/test_bitcoin
  $ src/test/test_bitcoin -t rpc_tests/rpc_format_monetary_values -t util_tests/util_FormatMoney
  ```

ACKs for top commit:
  laanwj:
    re-ACK 1f05dbd06d896849d16b026bfc3315ee8b73a89f

Tree-SHA512: 5aaeb8e2178f1597921f53c12bdfc2f3d5993d10c41658dcd25943e54e8cc2116a411bc71d928f890b33bc0b3761a8ee4449b0532bce41125b6c60692808c8c3

0 files changed, 0 insertions, 0 deletions