[llvm] [SandboxIR][NFC] Factor out common test for CastInst subclasses (PR #101410)

[via llvm-commits]

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@@ -34,6 +34,8 @@ struct SandboxIRTest : public testing::Test {
         return &BB;
     llvm_unreachable("Expected to find basic block!");
   }
+  template <typename SubclassT, sandboxir::Instruction::Opcode OpcodeT>
+  void testCastInst(const char *IRToParse, Type *SrcTy, Type *DstTy);
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vporpo wrote:

> I kinda like making this a top level static template function and shuffling around some parameters (e.g. separating the parseIR and testCastInst, passing M to testCastInst), but up to you

This is what I was planning initially, which is why I placed the function right above the tests. Let me try it once again but this time I will make `parseIR()` a top level static function that returns the Module, so that I can use it from within the tests.

https://github.com/llvm/llvm-project/pull/101410