[llvm] [Support] Report EISDIR when opening a directory (PR #79880)

[via llvm-commits]

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@@ -1296,6 +1296,29 @@ TEST_F(FileSystemTest, UTF8ToUTF16DirectoryIteration) {
 }
 #endif
 
+TEST_F(FileSystemTest, OpenDirectoryAsFileForRead) {
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azhan92 wrote:

Sure, which other file would you suggest? 

https://github.com/llvm/llvm-project/pull/79880