compiletest: Remove the magic hacks for finding output with `lto=thin`

This hack was intended to handle the case where `-Clto=thin` causes the
compiler to emit multiple output files (when producing LLVM-IR or assembly).

The hack only affects 4 tests, of which 3 are just meta-tests for the hack
itself. The one remaining test that motivated the hack currently doesn't even
need it!

(`tests/codegen/issues/issue-81408-dllimport-thinlto-windows.rs`)

1 files changed, 0 insertions, 6 deletions

diff --git a/tests/codegen/thin-lto.rs b/tests/codegen/thin-lto.rs
deleted file mode 100644
index 4339d20532e..00000000000
--- a/tests/codegen/thin-lto.rs
+++ /dev/null
@@ -1,6 +0,0 @@
-//@ compile-flags: -O -C lto=thin -C prefer-dynamic=no
-//@ only-x86_64-unknown-linux-gnu
-
-// CHECK: main
-
-pub fn main() {}