Add tests for declerations using multiple attributes with @ignoreDeprecationWarnings

Author: NSAntoine

test/attr/ignore_deprecation_warnings.swift

@@ -52,4 +52,14 @@ class anotherType {
 
     let shouldntWarn1 = deprecatedType()
     let shouldntWarn2 = deprecatedFuncWithReturnValue2()
-}
+}
+
+@inlinable
+@ignoreDeprecationWarnings
+func multipleAttrsFunc() -> deprecatedType {
+    return deprecatedType()
+}
+
+@ignoreDeprecationWarnings
+@available(iOS 15.0, *)
+var multipleAttrsVar = 3