findDecompiledDeclaration: find builtIns more accurately

Use resolveScope of a reference to help searching for builtIn binaries
Do not search non-builtIn descriptors in random scopes

compiler/tests-common/org/jetbrains/kotlin/codegen/forTestCompile/ForTestCompileRuntime.java

@@ -56,6 +56,11 @@ public class ForTestCompileRuntime {
         return assertExists(new File("dist/kotlinc/lib/kotlin-script-runtime.jar"));
     }
 
+    @NotNull
+    public static File runtimeSourcesJarForTests() {
+        return assertExists(new File("dist/kotlinc/lib/kotlin-runtime-sources.jar"));
+    }
+
     // TODO: Do not use these classes, remove them after stdlib tests are merged in the same build as the compiler
     @NotNull
     @Deprecated