[lld] [lld][WebAssembly] Preserve LTO stub deps for bitcode symbols (PR #173235)

[Sam Clegg via llvm-commits]

================
@@ -1,6 +1,10 @@
 ## The function `bar` is declared in stub.so and depends on `foo` which is
 ## defined in an LTO object.  We also test the case where the LTO object is
 ## with an archive file.
+## The function `baz` is declared in stub.so and depends on `quux`, and both
+## `baz` and `quux` are defined in an LTO object. When `baz` is DCE'd and
+## becomes undefined in the LTO process, `quux` should still be preserved and
+## exported.
----------------
sbc100 wrote:

The stub library symbol should not be used in the case that a definition exists in the program being linked.

https://github.com/llvm/llvm-project/pull/173235