[clang-tools-extra] [clang-tidy] Adds readability-redundant-const check (PR #189733)

[Baranov Victor via cfe-commits]

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@@ -0,0 +1,171 @@
+// RUN: %check_clang_tidy -std=c++11-or-later %s readability-redundant-const %t
+
+struct Foo {};
+
+constexpr int n1 = 10;
+const int n2 = 20;
+constexpr Foo n3 = {};
+
+constexpr const int p1 = 10;
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vbvictor wrote:

can we add tests with 
constexpr int const p2 = 0
constexpr const int const p2 = 0


https://github.com/llvm/llvm-project/pull/189733