Add equivalent safepoint test cases for basic blocks.

cranelift/filetests/filetests/safepoint/call.clif

@@ -1,7 +1,6 @@
 test safepoint
 set enable_safepoints=true
 target x86_64
-feature !"basic-blocks"
 
 function %direct() -> r64 {
     fn0 = %none()
@@ -12,9 +11,11 @@ ebb0:
     call fn0()
     v1 = call fn1()
     v2, v3 = call fn2()
-    brz v2, ebb1 
-    return v1
+    brz v2, ebb2
+    jump ebb1
 ebb1:
+    return v1
+ebb2:
     v4 = call fn1()
     return v3
 }
@@ -39,12 +40,15 @@ ebb1:
 ; nextln:   safepoint v1
 ; nextln:   v2, v10 = call_indirect sig2, v7()
 ; nextln:   v3 = spill v10
-; nextln:   brz v2, ebb1
-; nextln:   v11 = fill v1
+; nextln:   brz v2, ebb2
+; nextln:   jump ebb1
+; nextln: 
+; nextln: ebb1:
+; nextln:   v11 = fill.r64 v1
 ; nextln:   regmove v11, %r15 -> %rax
 ; nextln:   return v11
 ; nextln: 
-; nextln: ebb1:
+; nextln: ebb2:
 ; nextln:   v8 = func_addr.i64 fn1
 ; nextln:   safepoint v3
 ; nextln:   v4 = call_indirect sig1, v8()