[compiler-rt] [compiler-rt] [libFuzzer] Fix merge-posix.test file size test (PR #168137)

[Andrew Haberlandt via llvm-commits]

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@@ -14,7 +14,7 @@ RUN: echo ....U. > %tmp/T2/2
 RUN: echo ...Z.. > %tmp/T2/3
 RUN: echo ...Z.. > %tmp/T2/4
 RUN: echo ....E. > %tmp/T2/5
-RUN: echo .....R > %tmp/T2/6
+RUN: (echo .....R; for i in {1..1024}; do echo -n X; done) > %tmp/T2/6
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ndrewh wrote:

This is another option:

```
RUN: %python -c "f = open('%tmp/T2/6', 'wb'); f.write(b'.....R'.ljust(1025, 'X')); f.close()"
```

https://github.com/llvm/llvm-project/pull/168137