[AST][test] Add regression test forPointerExprEvaluator::VisitCXXNewExpr

This assert was failing:
assert(CAT && "unexpected type for array initializer");

until this patch landed:
9a7eda1
PR45350: Handle unsized array CXXConstructExprs in constant evaluation

Author: jkorous-apple

clang/test/AST/regression-new-expr-crash.cpp

@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only %s
+
+struct Bar {int a;};
+const Bar arr[2] = {{1}};
+
+struct Foo {};
+
+const int b = 2;
+
+void foo(int a) {
+  Foo *foo_array;
+  foo_array = new Foo[arr[0].a];
+}