[JniZero] Add extra constructor to ScopedJava{Local|Global}Ref

Webrtc currently has mirror classes to jni_zero's ScopedJavaLocalRef and
ScopedJavaGlobalRef that have extra constructors that take both a
JavaRef as well as a JNIEnv. To help with the migration, we are adding
those constructors to the original classes as well.

Bug: 325408567
Change-Id: Ia099e059ec2481a5703731b063ad854126bdc677
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5424954
Commit-Queue: Mohamed Heikal <mheikal@chromium.org>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1284647}