Add a basic TargetARM32 skeleton which knows nothing.

tests_lit/llvm2ice_tests/arith-opt.ll

 ; This is a very early test that just checks the representation of i32
 ; arithmetic instructions.  No assembly tests are done.
 
 ; REQUIRES: allow_dump
 
 ; RUN: %p2i -i %s --filetype=asm --args --verbose inst -threads=0 | FileCheck %s
 
+; TODO(jvoung): Enable test when it does not llvm::report_fatal_error.
+; The test runner wrappers don't handle error expected errors
+; so we can't just "not" the command.
+; RUIN: %if --need=target_ARM32 --command %p2i -i %s --filetype=asm \
+; RUIN:   --args --verbose inst -threads=0 --target arm32 \
+; RUIN:   | %if --need=target_ARM32 --command FileCheck %s --check-prefix ARM32
+
 define i32 @Add(i32 %a, i32 %b) {
 ; CHECK: define i32 @Add
 entry:
   %add = add i32 %b, %a
 ; CHECK: add
   tail call void @Use(i32 %add)
 ; CHECK: call Use
   ret i32 %add
 }
 
@@ skipping 93 matching lines @@
 
 ; Check for a valid addressing mode in the x86-32 mul instruction when
 ; the second source operand is an immediate.
 define i64 @MulImm() {
 entry:
   %mul = mul i64 3, 4
   ret i64 %mul
 }
 ; CHECK-LABEL: MulImm
 ; CHECK-NOT: mul {{[0-9]+}}