"foo" is at 0x2010. This corrects the expected output for .long and
.word referencing foo, showing a problem with relocation handling.
* testsuite/ld-pe/aarch64.d: Correct expected output.
This adds the remaining pe-aarch64 relocations, and gets them working.
It also brings in the constant directives from ELF, as otherwise .word
would be 2 rather than 4 bytes, and .xword and .dword wouldn't be
defined.