Add Om1 lowering with no optimizations

tests_lit/llvm2ice_tests/select-opt.ll

-; RUIN: %llvm2ice %s | FileCheck %s
-; RUIN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
+; Simple test of the select instruction.  The CHECK lines are only
+; checking for basic instruction patterns that should be present
+; regardless of the optimization level, so there are no special OPTM1
+; match lines.
+
+; RUIN: %llvm2ice -O2 --verbose none %s | FileCheck %s
+; RUN: %llvm2ice -Om1 --verbose none %s | FileCheck %s
+; RUN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
 ; RUN: %llvm2iceinsts %s | %szdiff %s | FileCheck --check-prefix=DUMP %s
 ; RUN: %llvm2iceinsts --pnacl %s | %szdiff %s \
 ; RUN:                           | FileCheck --check-prefix=DUMP %s
 
 define void @testSelect(i32 %a, i32 %b) {
 entry:
   %cmp = icmp slt i32 %a, %b
   %cond = select i1 %cmp, i32 %a, i32 %b
   tail call void @useInt(i32 %cond)
   %cmp1 = icmp sgt i32 %a, %b
   %cond2 = select i1 %cmp1, i32 10, i32 20
   tail call void @useInt(i32 %cond2)
   ret void
 }
 
 declare void @useInt(i32)
 
 ; CHECK:      .globl testSelect
 ; CHECK:      cmp
 ; CHECK:      cmp
 ; CHECK:      call useInt
 ; CHECK:      cmp
 ; CHECK:      cmp
 ; CHECK:      call useInt
 ; CHECK:      ret
 
 ; ERRORS-NOT: ICE translation error
 ; DUMP-NOT: SZ