Bug fix: A1 invariant failure - revert if amount to repay is 0, consistently update `t0debInAuction` accumulator

[grandizzy]

Description of change

High level

• Issue 1: bug in updating t0DebtInAuction when auction settled with repayDebt (A1 invariant violation)

  • auction was settled but the quote token amount calculated to repay was rounded down to 0
  • since t0 debt in auction accumulator was updated only when token amount to repay was not 0, the t0debtInAuction accumulator wasn't updated, leaving it in an inconsistent state
  • Fixed by reverting with InvalidAmount if amount calculated is 0 and by always updating t0debtInAuction accumulator when there's a t0 auction debt change (and not constrained by the amount of quote tokens to be paid. Same applied in case of pledged collateral too). Minor gas savings as contract size as result.t0DebtInAuctionChange != 0 is now performed only once

• Issue 2: fix invariant failure due to inconsistent LUP calculation in PoolInfoUtils by updating addQuoteToken handler to use wdiv when calculating debt

• Issue 3: fix invariant reserves failure on bucket take where first take penalty was applied to current borrower debt instead borrower t0 debt

Contract size

Pre Change

============ Deployment Bytecode Sizes ============
  ERC721Pool               -  24,404B  (99.30%)
  ERC20Pool                -  23,632B  (96.15%)

Post Change

============ Deployment Bytecode Sizes ============
  ERC721Pool               -  24,384B  (99.21%)
  ERC20Pool                -  23,612B  (96.07%)

Gas usage

Pre Change

| Function Name                        | min             | avg    | median | max     | # calls |
| addQuoteToken                        | 122500          | 179774 | 164363 | 715163  | 60004   |
| bucketTake                           | 309224          | 327865 | 327866 | 346507  | 4       |
| drawDebt                             | 253215          | 298204 | 272111 | 812414  | 136003  |
| kick                                 | 149467          | 223488 | 221980 | 1034805 | 48000   |
| kickWithDeposit                      | 199590          | 277221 | 273367 | 1000575 | 8000    |
| moveQuoteToken                       | 270677          | 270677 | 270677 | 270677  | 1       |
| removeQuoteToken                     | 147296          | 171445 | 176084 | 198249  | 4000    |
| repayDebt                            | 576921          | 609077 | 598969 | 757339  | 16002   |
| settle                               | 350544          | 350544 | 350544 | 350544  | 1       |
| take                                 | 81772           | 83349  | 83084  | 315391  | 15998   |

Post Change

| Function Name                        | min             | avg    | median | max     | # calls |
| addQuoteToken                        | 122500          | 179774 | 164363 | 715163  | 60004   |
| bucketTake                           | 309224          | 327865 | 327866 | 346507  | 4       |
| drawDebt                             | 253186          | 298177 | 272082 | 812414  | 136003  |
| kick                                 | 149467          | 223488 | 221980 | 1034805 | 48000   |
| kickWithDeposit                      | 199590          | 277221 | 273367 | 1000575 | 8000    |
| moveQuoteToken                       | 270677          | 270677 | 270677 | 270677  | 1       |
| removeQuoteToken                     | 147296          | 171445 | 176084 | 198249  | 4000    |
| repayDebt                            | 576921          | 609077 | 598969 | 757339  | 16002   |
| settle                               | 350544          | 350544 | 350544 | 350544  | 1       |
| take                                 | 81772           | 83349  | 83084  | 315391  | 15998   |