Disable running checkers by default (#4644)

* Make checkers be disabled by default

* Allow running checkers in test launcher

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

@@ -1,3 +1,5 @@
+import kotlin.native.Platform
+
 // The following 2 singletons are unused. However, since we are generating ObjC bindings for them,
 // they should be marked as used, so that the code generator emits their deinitialization.
 
@@ -10,3 +12,7 @@ class B {
         fun foo() = 2
     }
 }
+
+fun enableMemoryChecker() {
+    Platform.isMemoryLeakCheckerActive = true
+}

kotlin-native/backend.native/tests/framework/kt42397/test.swift

@@ -7,6 +7,7 @@ class Results {
 
 func runTestKt42397(pointer: UnsafeMutableRawPointer) -> UnsafeMutableRawPointer? {
     autoreleasepool {
+        KnlibraryKt.enableMemoryChecker()
         let results = pointer.bindMemory(to: Results.self, capacity: 1).pointee
         results.aFoo = A().foo()
         results.bFoo = B.Companion().foo()