p2p: fix infinite loop in addrbook (#3232)

* failing test

* fix infinite loop in addrbook

There are cases where we only have a small number of addresses marked
good ("old"), but the selection mechanism keeps trying to select more of these
addresses, and hence ends up in an infinite loop. Here we fix this to
only try and select such "old" addresses if we have enough of them. Note this
means, if we don't have enough of them, we may return more "new"
addresses than otherwise expected by the newSelectionBias.

This whole GetSelectionWithBias method probably needs to be rewritten,
but this is a quick fix for the issue.

* changelog

* fix infinite loop if not enough new addrs

* fix another potential infinite loop

if a.nNew == 0 -> pickFromOldBucket=true, but we don't have enough items
  (a.nOld > len(oldBucketToAddrsMap) false)

* Revert "fix another potential infinite loop"

This reverts commit 146540c112.

* check num addresses instead of buckets, new test

* fixed the int division

* add slack to bias % in test, lint fixes

* Added checks for selection content in test

* test cleanup

* Apply suggestions from code review

Co-Authored-By: ebuchman <ethan@coinculture.info>

* address review comments

* change after  Anton's review comments

* use the same docker image we use for testing

when building a binary for localnet

* switch back to circleci classic

* more review comments

* more review comments

* refactor addrbook_test

* build linux binary inside docker

in attempt to fix

```
--> Running dep
+ make build-linux
GOOS=linux GOARCH=amd64 make build
make[1]: Entering directory `/home/circleci/.go_workspace/src/github.com/tendermint/tendermint'
CGO_ENABLED=0 go build -ldflags "-X github.com/tendermint/tendermint/version.GitCommit=`git rev-parse --short=8 HEAD`" -tags 'tendermint' -o build/tendermint ./cmd/tendermint/
p2p/pex/addrbook.go:373:13: undefined: math.Round
```

* change dir from /usr to /go

* use concrete Go version for localnet binary

* check for nil addresses just to be sure

Makefile

@@ -269,7 +269,7 @@ build-docker:
 ### Local testnet using docker
 
 # Build linux binary on other platforms
-build-linux:
+build-linux: get_tools get_vendor_deps
 	GOOS=linux GOARCH=amd64 $(MAKE) build
 
 build-docker-localnode: