Add tools for checking Java and C# output.

tools/make_java_csharp_arena_base:
tools/make_java_csharp_arena_diff:
    Add these scripts, which can be used to check whether the output
    of a new compiler in Java and C# grades is bit-identical to the output
    of a known-good old compiler. This is particularly useful on machines
    that can't check the correctness of the output in these grades
    because they don't have Java or C# compilers installed.

tools/make_java_csharp_arena_diff

@@ -0,0 +1,43 @@
+#!/bin/sh
+# vim: ft=sh ts=4 sw=4 et
+#
+# This script is documented in the companion script make_java_csharp_base.
+
+if test "${TEST_MMC}" = ""
+then
+    echo "make_java_csharp_diff: you need to set TEST_MMC in the environment"
+    exit 1
+fi
+
+root=`/bin/pwd`
+
+/bin/rm -fr arena.java arena.csharp > /dev/null 2>&1
+cp -rp arena.base arena.java
+cp -rp arena.base arena.csharp
+
+cd ${root}/arena.java
+for f in *.m
+do
+    echo === JAVA ${f} ===
+    ${TEST_MMC} --grade java --target-code-only ${f}
+done
+
+cd ${root}/arena.csharp
+for f in *.m
+do
+    echo === CSHARP ${f} ===
+    ${TEST_MMC} --grade csharp --target-code-only ${f}
+done
+
+cd ${root}
+diff -ur arena.base.java arena.java > DIFF.ARENA.JAVA 2>&1
+diff -ur arena.base.csharp arena.csharp > DIFF.ARENA.CSHARP 2>&1
+
+echo JAVA DIFF START
+cat DIFF.ARENA.JAVA
+echo JAVA DIFF END
+echo CSHARP DIFF START
+cat DIFF.ARENA.CSHARP
+echo CSHARP DIFF END
+
+exit 0