cmd/compile/internal/gc: inline autogenerated (*T).M wrappers

cmd/compile/internal/gc: inline autogenerated (*T).M wrappers

Currently all inlining of autogenerated wrappers is disabled,
because it causes build failures, when indexed export format is enabled.
Turns out we can reenable it for common case of (*T).M wrappers.
This fixes most performance degradation of 1.11 vs 1.10.

encoding/binary:
name                    old time/op   new time/op   delta
ReadSlice1000Int32s-6    14.8µs ± 2%   11.5µs ± 2%  -22.01%  (p=0.000 n=10+10)
WriteSlice1000Int32s-6   14.8µs ± 2%   11.7µs ± 2%  -20.95%  (p=0.000 n=10+10)

bufio:
name           old time/op    new time/op    delta
WriterFlush-6    32.4ns ± 1%    28.8ns ± 0%  -11.17%  (p=0.000 n=9+10)

sort:
SearchWrappers-6       231ns ± 1%   231ns ± 0%     ~     (p=0.129 n=9+10)
SortString1K-6         365µs ± 1%   298µs ± 1%  -18.43%  (p=0.000 n=9+10)
SortString1K_Slice-6   274µs ± 2%   276µs ± 1%     ~     (p=0.105 n=10+10)
StableString1K-6       490µs ± 1%   373µs ± 1%  -23.73%  (p=0.000 n=10+10)
SortInt1K-6            210µs ± 1%   142µs ± 1%  -32.69%  (p=0.000 n=10+10)
StableInt1K-6          243µs ± 0%   151µs ± 1%  -37.75%  (p=0.000 n=10+10)
StableInt1K_Slice-6    130µs ± 1%   130µs ± 0%     ~     (p=0.237 n=10+8)
SortInt64K-6          19.9ms ± 1%  13.5ms ± 1%  -32.32%  (p=0.000 n=10+10)
SortInt64K_Slice-6    11.5ms ± 1%  11.5ms ± 1%     ~     (p=0.912 n=10+10)
StableInt64K-6        21.5ms ± 0%  13.5ms ± 1%  -37.30%  (p=0.000 n=9+10)
Sort1e2-6              108µs ± 2%    83µs ± 3%  -23.26%  (p=0.000 n=10+10)
Stable1e2-6            218µs ± 0%   161µs ± 1%  -25.99%  (p=0.000 n=8+9)
Sort1e4-6             22.6ms ± 1%  16.8ms ± 0%  -25.45%  (p=0.000 n=10+7)
Stable1e4-6           67.6ms ± 1%  49.7ms ± 0%  -26.48%  (p=0.000 n=10+10)
Sort1e6-6              3.44s ± 0%   2.55s ± 1%  -26.05%  (p=0.000 n=8+9)
Stable1e6-6            13.7s ± 0%    9.9s ± 1%  -27.68%  (p=0.000 n=8+10)

Fixes #27621
Updates #25338

Change-Id: I6fe633202f63fa829a6ab849c44d7e45f8835dff
Reviewed-on: https://go-review.googlesource.com/c/135697
Run-TryBot: Ilya Tocar <ilya.tocar@intel.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>