rustc: Update LLVM, remove dead wasm code

This commit updates the LLVM branch to the rebased version of the
upstream release/8.x branch. This includes a wasm patch which means that
the `rewrite_imports` pass in rustc is no longer needed (yay!) and we
can instead rely on `wasm-import-module`, an attribute we're already
emitting, to take care of all the work.

1 files changed, 0 insertions, 0 deletions

diff --git a/src/llvm-project b/src/llvm-project
-Subproject 73a75d35b9776d56160fa3200aca4a970ae49b6
+Subproject 38ad31bde8ff681d862dc0f96930a5dd9b7a472