Remove unused code related to the removed `BINARY_SUBSCR` instruction

[tomasr8]

BINARY_SUBSCR was replaced with BINARY_OP and the NB_SUBSCR oparg in #129700 but there is still some code related to BINARY_SUBSCR that I believe can be removed. Some examples:

cpython/Include/internal/pycore_code.h

Lines 121 to 125 in e82c2ca

	typedef struct {
	_Py_BackoffCounter counter;
	} _PyBinarySubscrCache;
	#define INLINE_CACHE_ENTRIES_BINARY_SUBSCR CACHE_ENTRIES(_PyBinarySubscrCache)

cpython/Lib/opcode.py

Lines 66 to 68 in e82c2ca

	"BINARY_SUBSCR": {
	"counter": 1,
	},

Linked PRs

• gh-131306: Remove unused code related to BINARY_SUBSCR #131307