refactor: move from io/ioutil to io and os package

[Juneezee]

Description

The io/ioutil package has been deprecated in Go 1.16 (See https://golang.org/doc/go1.16#ioutil). Since cosmos-sdk has upgraded to Go 1.17 (#9987), this PR replaces the existing io/ioutil functions with their new definitions in io and os packages.

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• confirmed the correct type prefix in the PR title
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[tac0turtle]

LGTM, thank you!!

[Juneezee]

@marbar3778 Thanks! The failing tests seem flaky

1. tests (01)

--- FAIL: TestIntegrationTestSuite (15.30s)
    network_test.go:21: setting up integration test suite
    network.go:202: acquiring test network lock
    network.go:212: preparing test network with chain-id "chain-Y760SM"
    network.go:476: starting test network...
    network_test.go:25: 
        	Error Trace:	network_test.go:25
        	            				suite.go:118
        	            				network_test.go:42
        	Error:      	Received unexpected error:
        	            	listen tcp 0.0.0.0:39611: bind: address already in use
        	Test:       	TestIntegrationTestSuite

2. liveness-test: It seems to be using a Go version older than 1.16.

snapshots/manager.go:146:9: undefined: io.ReadAll
snapshots/manager.go:241:17: undefined: io.NopCloser
note: module requires Go 1.17
# github.com/cosmos/cosmos-sdk/crypto/keyring
crypto/keyring/keyring.go:684:19: undefined: os.ReadFile
crypto/keyring/keyring.go:748:14: undefined: os.WriteFile
note: module requires Go 1.17
# github.com/cosmos/cosmos-sdk/server/grpc/gogoreflection
server/grpc/gogoreflection/serverreflection.go:221:14: undefined: io.ReadAll
note: module requires Go 1.17
# github.com/cosmos/cosmos-sdk/codec/unknownproto
codec/unknownproto/unknown_fields.go:361:20: undefined: io.ReadAll
note: module requires Go 1.17
make: *** [Makefile:115: build] Error 2
make: *** [Makefile:133: build-simd-linux] Error 2
Error: Process completed with exit code 2.

[tac0turtle]

liveness-test: It seems to be using a Go version older than 1.16.

https://github.com/cosmos/cosmos-sdk/blob/master/.github/workflows/test.yml#L227 seems like its setting 1.17, not sure where else the issue could be.

    	listen tcp 0.0.0.0:39611: bind: address already in use

maybe this was a fluke?

[codecov]

Codecov Report

Merging #10341 (db10308) into master (3637270) will decrease coverage by 0.02%.
The diff coverage is 62.50%.

❗ Current head db10308 differs from pull request most recent head 2e243be. Consider uploading reports for the commit 2e243be to get more accurate results

@@            Coverage Diff             @@
##           master   #10341      +/-   ##
==========================================
- Coverage   64.26%   64.23%   -0.03%     
==========================================
  Files         572      572              
  Lines       54142    54150       +8     
==========================================
- Hits        34795    34785      -10     
- Misses      17366    17385      +19     
+ Partials     1981     1980       -1     

Impacted Files	Coverage Δ
crypto/keyring/keyring.go	61.98% <0.00%> (ø)
simapp/state.go	0.00% <0.00%> (ø)
simapp/utils.go	21.62% <0.00%> (ø)
testutil/rest.go	0.00% <0.00%> (ø)
x/auth/client/cli/tx_multisign.go	0.00% <0.00%> (ø)
x/genutil/client/cli/gentx.go	0.00% <0.00%> (ø)
x/params/client/utils/utils.go	47.61% <0.00%> (ø)
x/simulation/event_stats.go	0.00% <0.00%> (ø)
x/auth/client/tx.go	36.26% <50.00%> (ø)
client/config/toml.go	55.55% <100.00%> (ø)
... and 13 more