Remove unused Object.opEquals(Object, Object)

It was added at 1e7ddf0425050e4f184532ec1d99316c37a8b2eb, but it seems to me that had not been used entirely.
complex.c is never called
Merge pull request #469 from WalterBright/rm_complex_d

complex.c is never called
build shared object file
Merge pull request #470 from WalterBright/build-so-obj

build shared object file
Merge pull request #452 from 9rnsr/fix_opeq2

Remove unused Object.opEquals(Object, Object)