[introspection] Skip verification of P/Invokes to the libhostpolicy l…

…ibrary.

System.Private.CoreLib.dll contains P/Invokes to a libhostpolicy library,
which isn't shipped.

An isssue has been filed to fix this in the runtime: dotnet/runtime#38543

tests/introspection/ApiPInvokeTest.cs

@@ -216,6 +216,10 @@ protected void Check (Assembly a)
 #endif
 						break;
 #if NET
+					case "libhostpolicy":
+						// There's no libhostpolicy library.
+						// https://github.com/dotnet/runtime/issues/38543
+						continue;
 					case "libSystem.Native":
 						path += ".dylib";
 						break;