[llvm] [NFC][ADT] Introduce a test harness for StringRefTest (PR #105500)

[Rahul Joshi via llvm-commits]

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@@ -16,20 +16,7 @@
 #include "gtest/gtest.h"
 using namespace llvm;
 
-namespace llvm {
-
-std::ostream &operator<<(std::ostream &OS, const StringRef &S) {
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jurahul wrote:

Updated change description as well to say:

* Delete unused << operators (googltest framework provides printers for StringRef and pairs).

https://github.com/llvm/llvm-project/pull/105500