[clang] Reapply "[clang] Limit lifetimes of temporaries to the full expression (#170517)" (PR #175816)

[Paul Kirth via cfe-commits]

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@@ -701,11 +701,12 @@ void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough,
 
   // If this is a normal cleanup, then having a prebranched
   // fallthrough implies that the fallthrough source unconditionally
-  // jumps here.
+  // jumps here, unless its for a lifetime marker.
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ilovepi wrote:

Hmm, looks like this isn't needed anymore. I had added this at some point in the past when trying to get things working, and it looks like I didn't clean up properly. I think we can drop all the changes to this file now. 

https://github.com/llvm/llvm-project/pull/175816