[llvm] [ADT] Bitset: add shift operators, word accessors, and etc (PR #193400)

[Jakub Kuderski via llvm-commits]

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@@ -294,4 +294,202 @@ TEST(BitsetTest, BitwiseOperators) {
                 TestXor128.test(127));
 }
 
+TEST(BitsetTest, ShiftOperators) {
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kuhar wrote:

Every new `TEST()` body in this PR contains only static_asserts; none has a runtime assertion; I think the latter are easier to debug in general. I'd keep one static assert per function to make sure it's useable in the constexpr setting but prefer `EXPECT_` elsewhere

https://github.com/llvm/llvm-project/pull/193400