[ASTImporter] Actually test ArrayInitLoopExpr in the array-init-loop-expr test.

[teemperor]

Summary

The array-init-loop-expr test is currently not testing the importing of ArrayInitLoopExprs.

This is because we import the S struct into the test.cpp context
and only do a copy-assignment in test.cpp, so the actual ArrayInitLoopExpr we wanted to
import is generated by clang directly in the target context. This means we actually
never test the importing of ArrayInitLoopExpr with this test, which becomes obvious
when looking at the missing test coverage for the respective VisitArrayInitLoopExpr method.

This patch moves the copy-assignment of our struct to the S.cpp context, which means
that test.cpp now actually has to import the ArrayInitLoopExpr.

[a_sidorin]

Wow, I totally overlooked this. Thank you!

cfe/trunk/test/Import/array-init-loop-expr/Inputs/S.cpp

 class S {
   int a[10];
 };
+
+void f() {
+  S s;
+  S copy = s;
+}

cfe/trunk/test/Import/array-init-loop-expr/test.cpp

 // RUN: clang-import-test -dump-ast -import %S/Inputs/S.cpp -expression %s | FileCheck %s
 // CHECK: CXXCtorInitializer
 // CHECK-NEXT: ArrayInitLoopExpr
 // CHECK-SAME: 'int [10]'
 
 // CHECK: ArrayInitIndexExpr
 
 void expr() {
-  S s;
-  S copy = s;
+  f();
 }