packages/crypto @ release-branch.go1.12

Filippo Valsorda 37a17fe027 internal/subtle: add Any/InexactOverlap (new package) and apply them across packages		%!s(int64=7) %!d(string=hai) anos
..
salsa	74b34b9dd6 all: make overlap rules wording consistent	%!s(int64=8) %!d(string=hai) anos
salsa20.go	37a17fe027 internal/subtle: add Any/InexactOverlap (new package) and apply them across packages	%!s(int64=7) %!d(string=hai) anos
salsa20_test.go	62fc357018 go.crypto/salsa20: add package.	%!s(int64=13) %!d(string=hai) anos