RFR: Purge StubRoutines::code3() block

[Aleksey Shipilev]

StubRoutines::code3() is gone long ago. Some debug code under #ifdef 0 still has
the reference to it, which shows up in merges. Let's purge:

$ hg diff
diff -r da56c185b6a9 src/cpu/aarch64/vm/sharedRuntime_aarch64.cpp
--- a/src/cpu/aarch64/vm/sharedRuntime_aarch64.cpp	Tue Jul 11 13:35:57 2017 +0200
+++ b/src/cpu/aarch64/vm/sharedRuntime_aarch64.cpp	Tue Jul 11 13:38:33 2017 +0200
@@ -538,10 +538,6 @@
       range_check(masm, rax, r11,
                   StubRoutines::code2()->code_begin(),
StubRoutines::code2()->code_end(),
                   L_ok);
-    if (StubRoutines::code3() != NULL)
-      range_check(masm, rax, r11,
-                  StubRoutines::code3()->code_begin(),
StubRoutines::code3()->code_end(),
-                  L_ok);
     const char* msg = "i2c adapter must return to an interpreter frame";
     __ block_comment(msg);
     __ stop(msg);

Thanks,
-Aleksey