testscripts: add go-fuzz-dep after cleaning up

Author: thepudds

testscripts/mod_outside_gopath.txt

@@ -16,6 +16,9 @@ cp go.mod_PRISTINE go.mod
 # in Go 1.11-1.13. (In 1.14, the default will likely be GO111MODULE=on).
 env GO111MODULE=auto
 
+# Because cmd/go now defaults to -mod=readonly, we need to explicitly add go-fuzz-dep.
+go get github.com/dvyukov/go-fuzz/go-fuzz-dep
+
 # Sanity check the module seems well formed.
 exec go list -m all
 stdout '^example.com/foo$'
@@ -38,6 +41,7 @@ stderr 'workers: \d+, corpus: '
 # Clean up.
 cp go.mod_PRISTINE go.mod
 rm foo-fuzz.zip
+go get github.com/dvyukov/go-fuzz/go-fuzz-dep
 
 # Second, we test with GO111MODULE=on, which will likely be the default in Go 1.14.
 env GO111MODULE=on
@@ -58,6 +62,7 @@ stderr 'workers: \d+, corpus: '
 # Clean up.
 cp go.mod_PRISTINE go.mod
 rm foo-fuzz.zip
+go get github.com/dvyukov/go-fuzz/go-fuzz-dep
 
 # Third, we test with GO111MODULE unset.
 # The meaning of this will likely change in Go 1.14, but given we are 
@@ -80,6 +85,7 @@ stderr 'workers: \d+, corpus: '
 # Clean up.
 cp go.mod_PRISTINE go.mod
 rm foo-fuzz.zip
+go get github.com/dvyukov/go-fuzz/go-fuzz-dep
 
 # Fourth, we test with GO111MODULE=off.
 # The meaning of this is unlikely to change in Go 1.14,
@@ -98,6 +104,7 @@ env GO111MODULE=off
 # Clean up (mainly in case we later add another test below).
 cp go.mod_PRISTINE go.mod
 rm foo-fuzz.zip
+go get github.com/dvyukov/go-fuzz/go-fuzz-dep
 
 # Define two modules.
 # example.com/foo has a fuzz function, and depends on example.com/bar.
@@ -109,9 +116,6 @@ require example.com/bar v0.0.0
 
 replace example.com/bar => ../bar
 
-// We need a require on go-fuzz to find go-fuzz-dep.
-require github.com/dvyukov/go-fuzz latest
-
 -- foo/fuzz.go --
 package foo