gh-109979: Auto-generate the target for DEOPT_IF() (#110193)

In Python/bytecodes.c, you now write
```
    DEOPT_IF(condition);
```
The code generator expands this to
```
    DEOPT_IF(condition, opcode);
```
where `opcode` is the name of the unspecialized instruction.
This works inside macro expansions too.

**CAVEAT:** The entire `DEOPT_IF(condition)` statement must be on a single line.
If it isn't, the substitution will fail; an error will be printed by the code generator
and the C compiler will report some errors.