cmd/internal/obj/ppc64: fix rebuilding of optab for asm tests
The end-to-end asm tests reinitialize the assembler using different
GOPPC64 values. This caused duplicate entries to amass from the
prefix and generated optab entries. This bug only affects the
asm end-to-end tests.
On reinitialization, optab contains the previous prefixedOptab
and optabGen entries, not just the initial values. Rework the
initialization to avoid the stale optab entries.
Change-Id: I310499915a5272ed0174ed8135d60788e6b4b716
Reviewed-on: https://go-review.googlesource.com/c/go/+/528316 Reviewed-by: Than McIntosh <thanm@google.com> Reviewed-by: Lynn Boger <laboger@linux.vnet.ibm.com> Reviewed-by: Bryan Mills <bcmills@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>