[15u] RFR 8254166: Zero: return-type warning in zeroInterpreter_zero.cpp

[Aleksey Shipilev]

Original fix;
   https://bugs.openjdk.java.net/browse/JDK-8254166
   https://git.openjdk.java.net/jdk/commit/7952c06b

cppInterpreter_zero.cpp was renamed to zeroInterpreter_zero.cpp by JDK-8239782.

So, 15u patch is:

diff -r 7b781c30206d src/hotspot/cpu/zero/cppInterpreter_zero.cpp
--- a/src/hotspot/cpu/zero/cppInterpreter_zero.cpp      Thu Oct 08 09:33:42 2020 +0000
+++ b/src/hotspot/cpu/zero/cppInterpreter_zero.cpp      Mon Oct 12 09:20:58 2020 +0200
@@ -99,7 +99,9 @@
      case T_DOUBLE:
      case T_VOID:
        return result;
-    default  : ShouldNotReachHere();
+    default:
+      ShouldNotReachHere();
+      return result; // silence compiler warnings
    }
  }

(I am going to use this later for backports to 11u and 8u).

Testing: tier{1,2}, Linux x86_64 Zero bootcycle-images

-- 
Thanks,
-Aleksey