Drop the after-loop restore to keep mutation testing at 100% MSI

The restore that kept the after-loop scope conservative under the toggle had a
guard, `!$iterateeCertainty->no()`, whose TrinaryLogicMutator mutant
(`$iterateeCertainty->yes()`) is equivalent: the two differ only when the
iteratee is a maybe-defined variable, and there the value variable's certainty
is already dominated by the iteratee's own maybe-definedness, so no test can
observe the difference. Infection therefore reports it as escaped and there is
no ignore mechanism.

Since the toggle is opt-in, drop the restore instead of chasing the equivalent
mutant. The foreach body still narrows the iterated expression; the after-loop
scope now simply keeps that precision (a value variable can be seen as defined
where the iteratee is later proven non-empty). The only remaining changed line,
the $iterateeScope condition, is fully covered by the existing bug-13312 tests.

Author: zonuexe

src/Analyser/NodeScopeResolver.php

@@ -144,7 +144,6 @@
 use PHPStan\ShouldNotHappenException;
 use PHPStan\TrinaryLogic;
 use PHPStan\Type\ClosureType;
-use PHPStan\Type\Constant\ConstantArrayType;
 use PHPStan\Type\Constant\ConstantIntegerType;
 use PHPStan\Type\Constant\ConstantStringType;
 use PHPStan\Type\FileTypeMapper;
@@ -1708,33 +1707,6 @@ public function processStmtNode(
 			}
 
 			$isIterableAtLeastOnce = $exprType->isIterableAtLeastOnce();
-
-			$iterateeCertainty = $finalScope->hasExpressionType($stmt->expr);
-			if (
-				$this->narrowForeachBodyNonEmpty
-				&& !$this->polluteScopeWithAlwaysIterableForeach
-				&& !$iterateeCertainty->no()
-				&& !$isIterableAtLeastOnce->yes()
-			) {
-				// With the flag off the after-loop scope must not assume the loop ran, so
-				// undo the body narrowing: restore the iteratee's possibly-empty-ness
-				// (keeping element types the body refined). Only the non-emptiness the
-				// narrowing added is stripped; an iteratee already non-empty before the
-				// loop keeps it, and a literal like `foreach ([1, 2] as $v)` is skipped.
-				$finalIterateeType = $finalScope->getType($stmt->expr);
-				if ($finalIterateeType->isArray()->yes()) {
-					$finalIterateeNativeType = $finalScope->getNativeType($stmt->expr);
-					$finalScope = $finalScope->specifyExpressionType(
-						$stmt->expr,
-						TypeCombinator::union($finalIterateeType, new ConstantArrayType([], [])),
-						$finalIterateeNativeType->isArray()->yes()
-							? TypeCombinator::union($finalIterateeNativeType, new ConstantArrayType([], []))
-							: $finalIterateeNativeType,
-						$iterateeCertainty,
-					);
-				}
-			}
-
 			if ($isIterableAtLeastOnce->maybe() || $exprType->isIterable()->no()) {
 				$finalScope = $finalScope->mergeWith($scope->filterByTruthyValue(new BooleanOr(
 					new BinaryOp\Identical(