Subzero: Fix nondeterministic behavior in constant pool creation.

tests_lit/llvm2ice_tests/undef.ll

Index: tests_lit/llvm2ice_tests/undef.ll
diff --git a/tests_lit/llvm2ice_tests/undef.ll b/tests_lit/llvm2ice_tests/undef.ll
index bf06b0522ff215bf0bc3c41ea366f4abec37d05c..d5823a9a5c7021843775aa944936bdf2c76fe5e6 100644
--- a/tests_lit/llvm2ice_tests/undef.ll
+++ b/tests_lit/llvm2ice_tests/undef.ll
@@ -38,7 +38,7 @@ define float @undef_float() {
 entry:
   ret float undef
 ; CHECK-LABEL: undef_float
-; CHECK: fld DWORD PTR {{.*}} .L$float$0
+; CHECK: fld DWORD PTR {{.*}} .L$float$00000000
 }
 
 define <4 x i1> @undef_v4i1() {
@@ -191,7 +191,7 @@ entry:
   %val = insertelement <4 x float> %arg, float undef, i32 0
   ret <4 x float> %val
 ; CHECK-LABEL: vector_insertelement_arg2
-; CHECK: {{movss|insertps}} {{.*}},DWORD PTR {{.*}} .L$float$0
+; CHECK: {{movss|insertps}} {{.*}},DWORD PTR {{.*}} .L$float$00000000
 }
 
 define float @vector_extractelement_v4f32_index_0() {