Revert of Revert of [Android] JUnit runner + gyp changes. (patchset #1 id:1 of https...

Revert of Revert of [Android] JUnit runner + gyp changes. (patchset #1 id:1 of https://codereview.chromium.org/597123002/)

Reason for revert:
Didn't help. We probably got scheduled on other, flakier Android devices which caused tests to start flaking, or something else is the root cause.

Original issue's description:
> Revert of [Android] JUnit runner + gyp changes. (patchset #15 id:280001 of https://codereview.chromium.org/574433003/)
>
> Reason for revert:
> Speculative revert: Android test started flaking a ton after this landed. Affected targets androidwebview_instrumentation_tests, chromeshell_instrumentation_tests, contentshell_instrumentation_tests. This CL seems the most likely in the blamelist of https://build.chromium.org/p/chromium.linux/builders/Android%20Tests/builds/15905.
>
> Original issue's description:
> > [Android] JUnit runner + gyp changes.
> >
> > This adds Java code for running junit tests, as well as gyp targets for
> > both runnable and non-runnable host-side JARs.
> >
> > BUG=316383
> >
> > Committed: https://crrev.com/2e56d4508e33de5fc60bbbb41c5a5d5534e88174
> > Cr-Commit-Position: refs/heads/master@{#296340}
>
> TBR=cjhopman@chromium.org,nyquist@chromium.org,aurimas@chromium.org,jbudorick@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=316383
>
> Committed: https://crrev.com/54b9408f8b18e3bf3a33343e375186e1949e8e86
> Cr-Commit-Position: refs/heads/master@{#296384}

TBR=cjhopman@chromium.org,nyquist@chromium.org,aurimas@chromium.org,jbudorick@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=316383

Review URL: https://codereview.chromium.org/596303002

Cr-Commit-Position: refs/heads/master@{#296406}