Allow conditional lit tests in Subzero, based on build flags.

tests_lit/llvm2ice_tests/addr-opt-multi-def-var.ll

 ; This is distilled from a real function that led to a bug in the
 ; address mode optimization code.  It followed assignment chains
 ; through non-SSA temporaries created from Phi instruction lowering.
 ;
 ; This test depends to some degree on the stability of "--verbose
 ; addropt" output format.
 
+; REQUIRES: x86-32
+; REQUIRES: allow_dump
 ; RUN: %p2i -i %s --args -O2 --verbose addropt | FileCheck %s
 
 declare i32 @_calloc_r(i32, i32, i32)
 
 define internal i32 @_Balloc(i32 %ptr, i32 %k) {
 entry:
   %gep = add i32 %ptr, 76
   %gep.asptr = inttoptr i32 %gep to i32*
   %0 = load i32* %gep.asptr, align 1
   %cmp = icmp eq i32 %0, 0
@@ skipping 39 matching lines @@
 ;   Instruction: [ 12]  %gep_array = mul i32 %k, 4
 ;     results in Base=%__4, Index=%k, Shift=2, Offset=0
 ;
 ; CHECK-NOT: results in Base=%__4,
 ;
   ret i32 %2
 
 return:                                           ; preds = %if.then
   ret i32 0
 }