gh-115999: Introduce helpers for (un)specializing instructions

[mpage]

Consolidate the code to specialize/unspecialize instructions into two helper functions and use them in _Py_Specialize_BinaryOp. The result is more concise and keeps all of the logic at the point where we decide to specialize/unspecialize an instruction.

If folks are amenable to this change, we can incrementally introduce their use as we work through making each specialization family thread-safe.

• Issue: Make the specializing interpreter thread-safe in --disable-gil builds #115999

[markshannon]

Looks good

[freakboy3742]

Not sure what is going on here, but this has caused a mass failure of buildbots... I'm seeing it on the iOS buildbot, where it's failing to build the macOS host build, before it even gets to the iOS build:

gcc -c -fno-strict-overflow -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall    -std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden  -I../../Include/internal -I../../Include/internal/mimalloc -IObjects -IInclude -IPython -I. -I../../Include    -DPy_BUILD_CORE -o Python/specialize.o ../../Python/specialize.c
../../Python/specialize.c:2801:5: error: call to undeclared function 'SET_OPCODE_OR_RETURN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    SET_OPCODE_OR_RETURN(instr, CONTAINS_OP);
    ^
1 error generated.
make: *** [Python/specialize.o] Error 1
program finished with exit code 2
elapsedTime=28.356593

[colesbury]

@freakboy3742 - it's fixed in main now (by @Eclips4)

[mpage]

Not sure what is going on here, but this has caused a mass failure of buildbots... I'm seeing it on the iOS buildbot, where it's failing to build the macOS host build, before it even gets to the iOS build:

gcc -c -fno-strict-overflow -Wsign-compare -Wunreachable-code -DNDEBUG -g -O3 -Wall    -std=c11 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Wstrict-prototypes -Werror=implicit-function-declaration -fvisibility=hidden  -I../../Include/internal -I../../Include/internal/mimalloc -IObjects -IInclude -IPython -I. -I../../Include    -DPy_BUILD_CORE -o Python/specialize.o ../../Python/specialize.c
../../Python/specialize.c:2801:5: error: call to undeclared function 'SET_OPCODE_OR_RETURN'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    SET_OPCODE_OR_RETURN(instr, CONTAINS_OP);
    ^
1 error generated.
make: *** [Python/specialize.o] Error 1
program finished with exit code 2
elapsedTime=28.356593

Sorry this was my fault. I merged this after #126450 was merged, without merging main into this PR first. This should be fixed by #126517.