Address review: remove _PyUop_Uncached from is_terminator

is_terminator() is only called before stack_allocate, where opcodes
are always base opcodes. Use the raw opcode directly with an assert.

In sanity_check (which sees replicated opcodes post-stack_allocate),
inline the terminator check using the already-computed base_opcode.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: eendebakpt

Python/optimizer.c

@@ -601,10 +601,8 @@ add_to_trace(
 static int
 is_terminator(const _PyUOpInstruction *uop)
 {
-    int opcode = _PyUop_Uncached[uop->opcode];
-    if (opcode == 0) {
-        opcode = uop->opcode;
-    }
+    int opcode = uop->opcode;
+    assert(opcode <= MAX_UOP_ID);
     return (
         opcode == _EXIT_TRACE ||
         opcode == _DEOPT ||
@@ -1348,7 +1346,10 @@ sanity_check(_PyExecutorObject *executor)
             CHECK(inst->format == UOP_FORMAT_JUMP);
             CHECK(inst->error_target < executor->code_size);
         }
-        if (is_terminator(inst)) {
+        if (base_opcode == _EXIT_TRACE ||
+            base_opcode == _DEOPT ||
+            base_opcode == _JUMP_TO_TOP ||
+            base_opcode == _DYNAMIC_EXIT) {
             ended = true;
             i++;
             break;