.*: revive from unused_parameters

[arvindbr8]

part of #7500

unused_parameters linters issue from revive were bypassed earlier. This is an attempt to fix that.

This PR also modifies vet:

• revive earlier did not error when there was output. I added -set_exit_status=1 to do that
• we should exclude reflection/test/grpc_testing_not_regenerate/
• remove the bypass for unused-parameters

RELEASE NOTES: none

[codecov]

Codecov Report

Attention: Patch coverage is 76.81159% with 16 lines in your changes missing coverage. Please review.

Project coverage is 81.89%. Comparing base (845f62c) to head (8860c9c).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
credentials/oauth/oauth.go	0.00%	3 Missing ⚠️
mem/buffers.go	0.00%	2 Missing ⚠️
profiling/service/service.go	0.00%	2 Missing ⚠️
rpc_util.go	88.23%	2 Missing ⚠️
balancer/endpointsharding/endpointsharding.go	0.00%	1 Missing ⚠️
balancer_wrapper.go	0.00%	1 Missing ⚠️
channelz/service/service.go	85.71%	1 Missing ⚠️
credentials/alts/internal/testutil/testutil.go	50.00%	1 Missing ⚠️
credentials/tls/certprovider/store.go	0.00%	1 Missing ⚠️
grpclog/internal/logger.go	0.00%	1 Missing ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7577      +/-   ##
==========================================
+ Coverage   81.76%   81.89%   +0.12%     
==========================================
  Files         361      361              
  Lines       27825    27825              
==========================================
+ Hits        22752    22787      +35     
+ Misses       3866     3849      -17     
+ Partials     1207     1189      -18     

Files with missing lines	Coverage Δ
balancer/base/balancer.go	87.03% <100.00%> (+1.85%)	⬆️
balancer/pickfirst/pickfirst.go	83.73% <100.00%> (ø)
balancer/weightedroundrobin/balancer.go	80.51% <100.00%> (ø)
credentials/alts/internal/handshaker/handshaker.go	80.00% <100.00%> (+5.00%)	⬆️
credentials/insecure/insecure.go	81.81% <100.00%> (ø)
credentials/local/local.go	73.52% <100.00%> (ø)
credentials/xds/xds.go	88.88% <100.00%> (ø)
health/server.go	95.52% <100.00%> (ø)
internal/binarylog/method_logger.go	88.49% <100.00%> (ø)
internal/resolver/passthrough/passthrough.go	100.00% <100.00%> (ø)
... and 25 more

... and 17 files with indirect coverage changes

[dfawley]

Not a 100% thorough review, but I skimmed everything and LGTM.

[arvindbr8]

cc: @purnesh42H