Disable running checkers by default (#4644)

* Make checkers be disabled by default

* Allow running checkers in test launcher

kotlin-native/backend.native/tests/interop/kt42397/knlibrary.kt

@@ -1,5 +1,7 @@
 package knlibrary
 
+import kotlin.native.Platform
+
 // The following 2 singletons are unused. However, since we are generating C bindings for them,
 // they should be marked as used, so that the code generator emits their deinitialization.
 
@@ -8,3 +10,7 @@ object A {}
 class B {
     companion object {}
 }
+
+fun enableMemoryChecker() {
+    Platform.isMemoryLeakCheckerActive = true
+}

kotlin-native/backend.native/tests/interop/kt42397/test.cpp

@@ -6,6 +6,8 @@ int main() {
     auto t = std::thread([] {
         auto lib = testlib_symbols();
 
+        lib->kotlin.root.knlibrary.enableMemoryChecker();
+
         // Initialize A and B.Companion and get their stable pointers.
         auto a = lib->kotlin.root.knlibrary.A._instance();
         auto bCompanion = lib->kotlin.root.knlibrary.B.Companion._instance();