[PATCH] [libcxx] Cleanup and fix is_destructible and tests in C++03.

[Marshall Clow]

I'm unsure why we're testing for `__has_feature(cxx_noexcept)` in is_nothrow_destructible.pass.cpp

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Comment at: test/utilities/meta/meta.unary/meta.unary.prop/is_nothrow_destructible.pass.cpp:72
@@ -70,2 +71,3 @@
     test_is_not_nothrow_destructible<char[]>();
+    test_is_not_nothrow_destructible<char[][3]>();
 
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I like the idea of adding a test for an array of known bound, but did you mean `[3]` or `[][3]` ??

http://reviews.llvm.org/D6316