Fixes phpstan/phpstan#5865

Summary

When a void-typed method or function always throws an exception (but doesn't declare never as its return type), PHPStan was unable to detect that calls to it would always terminate execution. This caused false positive "loop condition is always true" errors for do-while and while loops whose bodies called such methods.

For example:

public function alwaysThrows(): void
{
    throw new \Exception();
}

public function test(): void
{
    do {
        $this->alwaysThrows();
    } while (true); // false positive: "Do-while loop condition is always true."
}

Approach

During method and function body analysis, NodeScopeResolver already tracks execution ends and whether the body always terminates (this is used by NeverRuleHelper to suggest the never return type). This PR stores that "always terminates" information in a lookup map (alwaysTerminatingCallables) keyed by the fully-qualified callable name, then consults it in findEarlyTerminatingExpr when processing:

• Instance method calls ($this->alwaysThrows())
• Static method calls (self::staticAlwaysThrows())
• Function calls (alwaysThrowsFunction())

First-class callable syntax (e.g. $this->method(...)) is explicitly excluded since it creates a closure rather than invoking the method.

Limitation: This only works when the called method/function is analyzed before the caller (same file, declaration order). Cross-file calls won't benefit from this detection — those cases would require declaring never as the return type.

Test plan

• Added tests/PHPStan/Rules/Comparison/data/bug-5865.php — do-while loop regression tests covering instance methods, variable conditions, never return type, static methods, and function calls
• Added tests/PHPStan/Rules/Comparison/data/bug-5865-while.php — analogous while loop regression tests
• Added test methods in DoWhileLoopConstantConditionRuleTest and WhileLoopAlwaysTrueConditionRuleTest
• All 11857 existing tests continue to pass
• PHPStan self-analysis passes with no errors