Write a run test for brz.i128;

cranelift/filetests/filetests/isa/x86/br-i128-run.clif

@@ -0,0 +1,38 @@
+test run
+target x86_64
+
+function %br_false() -> b1 {
+ebb0:
+    v10 = iconst.i64 0x42
+    v11 = iconst.i64 0x00
+    v0 = iconcat v10, v11
+    brz v0, ebb2
+    jump ebb1
+
+ebb1:
+    v1 = bconst.b1 true
+    return v1
+
+ebb2:
+    v2 = bconst.b1 false
+    return v2
+}
+; run
+
+function %br_true() -> b1 {
+ebb0:
+    v10 = iconst.i64 0x00
+    v11 = iconst.i64 0x00
+    v0 = iconcat v10, v11
+    brz v0, ebb2
+    jump ebb1
+
+ebb1:
+    v1 = bconst.b1 false
+    return v1
+
+ebb2:
+    v2 = bconst.b1 true
+    return v2
+}
+; run