Reland "JNI: Do not inhibit GC in GetStringCritical for compressed string."

It was accidentally reverted in https://r.android.com/1434215.

(cherry-pick of b2568693d783d53aa80f71fde4715995a1f695cc)

Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Change-Id: I7a4953ccde5bf4af1b697545c125ad9bdbe18088
1 file changed