cmd/internal/obj: print relocation type by name in -S output
The compiler/assembler's -S output prints relocation type
numerically, which is hard to understand. Every time I need to
count the relocation type constants to figure out which relocation
it actually is. Print the symbolic name instead.
Change-Id: I4866873bbae8b3dc0ee212609cb00280f9164243
Reviewed-on: https://go-review.googlesource.com/c/go/+/501856
TryBot-Result: Gopher Robot <gobot@golang.org> Reviewed-by: Than McIntosh <thanm@google.com>
Run-TryBot: Cherry Mui <cherryyz@google.com>