Add option to force filetype=asm for testing

tests_lit/llvm2ice_tests/loop-nest-depth.ll

Index: tests_lit/llvm2ice_tests/loop-nest-depth.ll
diff --git a/tests_lit/llvm2ice_tests/loop-nest-depth.ll b/tests_lit/llvm2ice_tests/loop-nest-depth.ll
index a899e50c0f263dbaf43d7f5f7b9a9ea8c512adca..63c9670a919e89ab3e8c82a0af8ee878b3476b06 100644
--- a/tests_lit/llvm2ice_tests/loop-nest-depth.ll
+++ b/tests_lit/llvm2ice_tests/loop-nest-depth.ll
@@ -2,9 +2,9 @@
 
 ; REQUIRES: allow_dump
 
-; Single threaded so that the dumps used for checking happen in order
+; Single threaded so that the dumps used for checking happen in order.
 ; RUN: %p2i --filetype=obj --disassemble -i %s --args -O2 --verbose=loop \
-; RUN: --threads=0 | FileCheck %s
+; RUN:     -log=%t --threads=0 && FileCheck %s < %t
 
 define internal void @test_single_loop(i32 %a32) {
 entry: