Revert "JNI Zero: Add support for @JniType("std::map<>")"

This reverts commit 9751b38f.

Reason for revert: Broke internal chrome:
https://ci.chromium.org/ui/p/chrome/builders/ci/android-arm-rel-ready/24606/overview

Original change's description:
> JNI Zero: Add support for @JniType("std::map<>")
>
> Serializes the Map to an Object[], and then populates a std::map (or
> similar).
>
> Bug: 326110639
> Change-Id: Iaa72e11ebac6c11a711845e99c98551969a7351f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5615691


> Commit-Queue: Andrew Grieve <agrieve@chromium.org>
> Reviewed-by: Mohamed Heikal <mheikal@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1313601}

Bug: 326110639
Change-Id: Ie434b43f9fb2c7aad51477ee4e9783ee48ae79d2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5621956


Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Commit-Queue: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Reviewed-by: Mohamed Heikal <mheikal@chromium.org>
Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#1313666}