Change integration test to return stable results

Author: tamasvajk

csharp/ql/integration-tests/all-platforms/standalone/CompilerMessage.expected

@@ -0,0 +1,4 @@
+extractorMessages
+| 5 |
+compilerDiagnostics
+| 4 |

csharp/ql/integration-tests/all-platforms/standalone/CompilerMessage.ql

@@ -0,0 +1,6 @@
+import csharp
+import semmle.code.csharp.commons.Diagnostics
+
+query predicate extractorMessages(int c) { c = count(ExtractorMessage msg) }
+
+query predicate compilerDiagnostics(int c) { c = count(Diagnostic diag) }