[dev.boringcrypto] cmd/compile: remove the awful boringcrypto kludge

CL 60271 introduced this “AwfulBoringCryptoKludge.”
iant approved that CL saying “As long as it stays out of master...”

Now that the rsa and ecdsa code uses boring.Cache, the
“boring unsafe.Pointer” fields are gone from the key structs, and this
code is no longer needed. So delete it.

With the kludge deleted, we are one step closer to being able to merge
dev.boringcrypto into master.

For #51940.

Change-Id: Ie549db14b0b699c306dded2a2163f18f31d45530
Reviewed-on: https://go-review.googlesource.com/c/go/+/395884
Reviewed-by: Ian Lance Taylor <[email protected]>
Reviewed-by: Ian Lance Taylor <[email protected]>

misc/boring/VERSION

@@ -1 +1 @@
-7
+8

src/cmd/compile/internal/amd64/versions_test.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// When using GOEXPERIMENT=boringcrypto, the test program links in the boringcrypto syso,
+// which does not respect GOAMD64, so we skip the test if boringcrypto is enabled.
 //go:build !boringcrypto
 
 package amd64_test

src/cmd/compile/internal/reflectdata/reflect.go

@@ -1156,33 +1156,6 @@ func writeType(t *types.Type) *obj.LSym {
  // for security, only the exported fields.
  case types.TSTRUCT:
  fields := t.Fields().Slice()
-
- // omitFieldForAwfulBoringCryptoKludge reports whether
- // the field t should be omitted from the reflect data.
- // In the crypto/... packages we omit an unexported field
- // named "boring", to keep from breaking client code that
- // expects rsa.PublicKey etc to have only public fields.
- // As the name suggests, this is an awful kludge, but it is
- // limited to the dev.boringcrypto branch and avoids
- // much more invasive effects elsewhere.
- omitFieldForAwfulBoringCryptoKludge := func(t *types.Field) bool {
- if t.Sym == nil || t.Sym.Name != "boring" || t.Sym.Pkg == nil {
- return false
- }
- path := t.Sym.Pkg.Path
- if t.Sym.Pkg == types.LocalPkg {
- path = base.Ctxt.Pkgpath
- }
- return strings.HasPrefix(path, "crypto/")
- }
- newFields := fields[:0:0]
- for _, t1 := range fields {
- if !omitFieldForAwfulBoringCryptoKludge(t1) {
- newFields = append(newFields, t1)
- }
- }
- fields = newFields
-
  for _, t1 := range fields {
  writeType(t1.Type)
  }