[compiler-rt] [profile] Implement a non-mmap path when reading profile files from a non-local filesystem (PR #131177)

[Hubert Tong via llvm-commits]

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@@ -0,0 +1,25 @@
+// RUN: mkdir -p %t.d && cd %t.d
+// RUN: rm -f *.profraw
+// RUN: %clang_pgogen %s -o a.out
+
+// Need to run a.out twice, the second time a merge will occur which will trigger an mmap.
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hubert-reinterpretcast wrote:

```suggestion
// Need to run a.out twice. On the second time, a merge will occur, which will
// trigger an mmap.
```

https://github.com/llvm/llvm-project/pull/131177