Sema: Don't diagnose isolated deinit availability in skipped function bodies.

As a follow-up fix for #83545, avoid
incorrectly diagnosing isolated deinit availability during module emission
jobs, which skip type checking non-inlinable function bodies and therefore
don't build accurate availability scopes for those bodies. It's ok to skip
these diagnostics during module emission since they should still be emitted
during compilation jobs.

Resolves rdar://161178785.

Author: tshortli

lib/Sema/TypeCheckAttr.cpp

@@ -135,6 +135,12 @@ class AttributeChecker : public AttributeVisitor<AttributeChecker> {
     }
 
     if (!getActorIsolation(nominal).isMainActor() && destructor->hasBody()) {
+      // In module emission jobs, type checking the body of the destructor may
+      // be skipped which means availability in the body cannot be diagnosed
+      // accurately.
+      if (destructor->isBodySkipped())
+        return;
+
       TypeChecker::checkAvailability(
           destructor->getBodySourceRange(), C.getIsolatedDeinitAvailability(),
           D->getDeclContext(),

test/Concurrency/deinit_isolation_availability.swift

@@ -2,6 +2,11 @@
 // RUN: %target-typecheck-verify-swift -swift-version 5 %s -strict-concurrency=complete -target %target-swift-6.1-abi-triple
 // RUN: %target-typecheck-verify-swift -swift-version 5 %s -strict-concurrency=complete -target %target-swift-6.1-abi-triple -target-min-inlining-version min -verify-additional-prefix inlining-
 
+// Test -emit-module configurations.
+
+// RUN: %target-swift-frontend -emit-module -verify -swift-version 5 %s -strict-concurrency=complete -target %target-swift-5.1-abi-triple -experimental-skip-non-inlinable-function-bodies -verify-additional-prefix inlining-
+// RUN: %target-swift-frontend -emit-module -verify -swift-version 5 %s -strict-concurrency=complete -target %target-swift-6.1-abi-triple -experimental-skip-non-inlinable-function-bodies -target-min-inlining-version min -verify-additional-prefix inlining-
+
 // REQUIRES: concurrency
 // REQUIRES: OS=macosx