[ELF] Check linker created dynamic variables

Check the values of _GLOBAL_OFFSET_TABLE_ and _DYNAMIC variables created by
linker.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@221857 91177308-0d34-0410-b5e6-96231b3b80d8
[ELF] Fix max-page-size option.

The user can use the max-page-size option and set the maximum page size. Dont
check for maximum allowed values for page size, as its what the kernel is
configured with.

Fix the test as well.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@221858 91177308-0d34-0410-b5e6-96231b3b80d8