Revert [llvm-objcopy] Allow strip symtab from executables and DSOs

Revert [llvm-objcopy] Allow strip symtab from executables and DSOs

This reverts r365193 (git commit 194f16b3548bcb23a7f0fd638778ed72edd18d37)

This patch doesn't work with binaries built w/ `--emit-relocs`, e.g.

```
$ echo 'int main() { return 0; }' | clang -Wl,--emit-relocs -x c - -o foo && llvm-objcopy --strip-unneeded foo
llvm-objcopy: error: 'foo': not stripping symbol '__gmon_start__' because it is named in a relocation
```

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365712 91177308-0d34-0410-b5e6-96231b3b80d8