Fix build instabilities on Travis CI

[mirkosertic]

See the following error for more:

[INFO] Tests run: 11, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 123.867 s - in de.[secure].bytecoder.complex.LuaTest
[INFO] Running de.[secure].bytecoder.complex.PromiseTest
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 1.961 s <<< FAILURE! - in de.[secure].bytecoder.complex.PromiseTest
[ERROR] testResolve backend=wasm preferStackifier=true minify=true exceptionsEnabled=false(de.[secure].bytecoder.complex.PromiseTest)  Time elapsed: 1.958 s  <<< ERROR!
org.openqa.selenium.WebDriverException: 
unknown error: Chrome failed to start: exited abnormally
  (unknown error: DevToolsActivePort file doesn't exist)
  (The process started from chrome location /usr/bin/google-chrome is no longer running, so ChromeDriver is assuming that Chrome has crashed.)
Build info: version: '3.141.59', revision: 'e82be7d358', time: '2018-11-14T08:17:03'
System info: host: 'localhost', ip: '127.0.0.1', os.name: 'Linux', os.arch: 'amd64', os.version: '4.15.0-1037-gcp', java.version: '1.8.0_222'
Driver info: driver.version: RemoteWebDriver
remote stacktrace: #0 0x563654ca6749 <unknown>

[mirkosertic]

https://stackoverflow.com/questions/50642308/webdriverexception-unknown-error-devtoolsactiveport-file-doesnt-exist-while-t

[mirkosertic]

Merged to master