Revert^2 "Optimize register mask and stack mask in stack maps."

This reverts commit 8b20b5c1.

Reason for revert: Retry submit unmodified after fixing the test.

Use BitTable to store the masks as well and move the
deduplication responsibility to the BitTable builders.

Don't generate entries for masks which are all zeros.
This saves 0.2% of .oat file size on both Arm64 and Arm.

Encode registers as (value+shift) due to tailing zeros.
This saves 1.0% of .oat file size on Arm64 and 0.2% on Arm.

Test: test-art-target-gtest-exception_test
Test: test-art-host-gtest-bit_table_test
Test: test-art-host-gtest-stack_map_test
Change-Id: Ib643776dbec3f051cc29cd13ff39e453fab5fae9