build: don't fail `make test` on source tarballs

Tries to achieve the same effect as
https://github.com/nodejs/node/pull/13658 without breaking source
tarballs. Presumably if `tools/eslint` wasn't there at all, people
would notice in the PR review!

PR-URL: https://github.com/nodejs/node/pull/15441
Fixes: https://github.com/nodejs/node/issues/14513
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

Makefile

@@ -922,7 +922,7 @@ cpplint:
 	@$(PYTHON) tools/cpplint.py $(CPPLINT_FILES)
 	@$(PYTHON) tools/check-imports.py
 
-ifneq ("","$(wildcard tools/eslint/bin/eslint.js)")
+ifneq ("","$(wildcard tools/eslint/)")
 lint:
 	@EXIT_STATUS=0 ; \
 	$(MAKE) jslint || EXIT_STATUS=$$? ; \
@@ -943,7 +943,6 @@ lint:
 	@echo "Linting is not available through the source tarball."
 	@echo "Use the git repo instead:" \
 		"$ git clone https://github.com/nodejs/node.git"
-	exit 1
 
 lint-ci: lint
 endif

vcbuild.bat

@@ -505,7 +505,7 @@ goto exit
 if defined enable_static goto exit
 if defined jslint_ci goto jslint-ci
 if not defined jslint goto exit
-if not exist tools\eslint\bin\eslint.js goto no-lint
+if not exist tools\eslint goto no-lint
 echo running jslint
 %config%\node tools\eslint\bin\eslint.js --cache --rule "linebreak-style: 0" --rulesdir=tools\eslint-rules --ext=.js,.md benchmark doc lib test tools
 goto exit
@@ -518,7 +518,7 @@ goto exit
 :no-lint
 echo Linting is not available through the source tarball.
 echo Use the git repo instead: $ git clone https://github.com/nodejs/node.git
-exit /b 1
+goto exit
 
 :create-msvs-files-failed
 echo Failed to create vc project files.