[clang] Make PCH's respect any VFS specified. (PR #106577)

[Jan Svoboda via cfe-commits]

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@@ -0,0 +1,26 @@
+// RUN: rm -rf %t
+// RUN: mkdir -p %t/From
+// RUN: mkdir -p %t/To
+// RUN: echo '#pragma once' > %t/From/B.h
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jansvoboda11 wrote:

Could you rewrite the test using `split-file`? That is much easier to read.

https://github.com/llvm/llvm-project/pull/106577