Enable String compression.

Test: m test-art-host (interpreter, JIT, AOT)
Test: m test-art-target on Nexus 6P (interpreter, JIT, AOT)
Test: Nexus 6P boots
Test: m ahat-test
Bug: 31040547
Change-Id: I2c2f74ca147b3ea98ef06f9c64553737d17d42fd
3 files changed