only show disassembly of optimized build

we can't really compare the disassembly of the debug build to
libcompiler-rt.a anyways

library/compiler-builtins/appveyor.yml

@@ -18,7 +18,6 @@ test_script:
   - cargo test
   - cargo test --release
   - CALL "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat"
-  - dumpbin /disasm target/debug/librustc_builtins.rlib || exit 0
   - dumpbin /disasm target/release/librustc_builtins.rlib || exit 0
 
 branches:

library/compiler-builtins/ci/script.sh

@@ -11,7 +11,6 @@ inspect() {
     $PREFIX$NM -g --defined-only target/**/debug/*.rlib
 
     set +e
-    $PREFIX$OBJDUMP -Cd target/**/debug/*.rlib
     $PREFIX$OBJDUMP -Cd target/**/release/*.rlib
     set -e