Remove ed25519 precompile

[gastonponti]

Description

Remove the CIP-25 as part of the CIP: celo-org/celo-proposals#392

Backwards compatibility

Part of the Gingerbread P2 Hard Fork

[github-actions]

Coverage from tests in ./e2e_test/... for ./consensus/istanbul/... at commit 0404e7a

coverage: 50.8% of statements across all listed packages

coverage:  63.2% of statements in consensus/istanbul
coverage:  42.7% of statements in consensus/istanbul/announce
coverage:  55.8% of statements in consensus/istanbul/backend
coverage:   0.0% of statements in consensus/istanbul/backend/backendtest
coverage:  24.3% of statements in consensus/istanbul/backend/internal/replica
coverage:  65.2% of statements in consensus/istanbul/core
coverage:  50.0% of statements in consensus/istanbul/db
coverage:   0.0% of statements in consensus/istanbul/proxy
coverage:  64.4% of statements in consensus/istanbul/uptime
coverage:  51.8% of statements in consensus/istanbul/validator
coverage:  79.2% of statements in consensus/istanbul/validator/random

[github-actions]

Test failures:
TestEthersJSCompatibilityDisableAfterGingerbread: e2e_test Checking getExchangeSpenders. spenders = [0x000000000000000000000000000000000000d028] Checking medianRate. numerator = 1000000000000000000000000 denominator = 1000000000000000000000000 Checking gas price minimum. cusdValue = 100000000 Checking getExchangeSpenders. spenders = [0x000000000000000000000000000000000000d028] Checking medianRate. numerator = 1000000000000000000000000 denominator = 1000000000000000000000000 Checking gas price minimum. cusdValue = 100000000 e2e_test.go:742: e2e_test.go:744:
This test report was produced by the test-summary action.  Made with ❤️ in Cambridge.

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: +0.08% 🎉

Comparison is base (1c5df77) 55.16% compared to head (520158f) 55.24%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2177      +/-   ##
==========================================
+ Coverage   55.16%   55.24%   +0.08%     
==========================================
  Files         676      676              
  Lines      114015   114015              
==========================================
+ Hits        62895    62989      +94     
+ Misses      47242    47177      -65     
+ Partials     3878     3849      -29     

Files Changed	Coverage Δ
core/vm/contracts.go	80.65% <ø> (ø)

... and 28 files with indirect coverage changes

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[karlb]

This is the minimal change to keep the diff as small as possible so directly before the release. The implementation can be removed in a PR after the hardfork.