Prepare for merging from rust-lang/rust

This updates the rust-version file to 8796b3b8b4ac6f38a80bf80ce89dd7bd7f92edd7.

src/tools/miri/rust-version

diff --git a/src/tools/miri/rust-version b/src/tools/miri/rust-version
index 596e757..329ee6a 100644
--- a/src/tools/miri/rust-version
+++ b/src/tools/miri/rust-version
@@ -1 +1 @@
-a0c97e3255e2b9140f131baec1c93eef57640d21
+8796b3b8b4ac6f38a80bf80ce89dd7bd7f92edd7