Keep template argument facts of catch and finally blocks - #6608

With unresolvedTemplateArguments (bleeding edge), a template argument site inside a catch block that ends by throwing or returning, or inside a finally block, was never resolved:

try {
	mayThrow();
} catch (\Exception $e) {
	$collection = new Collection([1]);
	takeInts($collection); // Collection<int> expected
	throw $e;
}
// Parameter #1 $collection of function takeInts expects Collection<int>, Collection<unresolved(1)> given.

TryCatchHandler leaves an always-terminating catch block out of the scope after the try-catch, and the finally block reaches it only through processFinallyScope(), which carries variable state. The facts the observation pass collected in those blocks were dropped with their scopes. The constraints of every block (try, each catch, finally) are now joined into the scope after the try-catch - constraints are a persistent collection deduplicated by node identity, so joining a shared prefix again costs nothing.

Found on Slevomat through the closure signature inference in #6604, which inherits the same observation pass.

• tests/PHPStan/Analyser/nsrt/template-argument-try-catch.php fails without the fix (Collection<unresolved(1)> for the throwing catch and the finally block).
• Turbo twin ported (TryCatchHandler.cpp), side-by-side / smoke green, expected version bumped.

🤖 Generated with Claude Code

https://claude.ai/code/session_01VpbB99tJfUmeArX74xqvHv