Generate not-null assertions on method parameters

Intrinsics.checkParameterIsNotNull() gets its caller's class and method names
from the stack trace to render them in an exception message.

Fix codegen tests because now it's now allowed to pass null to non-null
argument in tests

compiler/testData/codegen/notNullAssertions/noAssertionForPrivateMethod.kt

@@ -0,0 +1,4 @@
+class A {
+    private fun foo(s: String) {
+    }
+}