[clang] [CIR] Build out AST consumer patterns to reach the entry point into CIRGen (PR #91007)

[Chuanqi Xu via cfe-commits]

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@@ -0,0 +1,61 @@
+//===---- CIRGenAction.h - CIR Code Generation Frontend Action -*- C++ -*--===//
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ChuanqiXu9 wrote:

Should we move this header to `CIR` or `FrontendAction`? Currently it lives in `CIRFrontendAction` but its implementation file lives in `FrontendAction`

https://github.com/llvm/llvm-project/pull/91007