Do not create 4-byte sequences in `ConvertUtf16ToModifiedUtf8()`

This encoding was different from the encoding in dex files
and this caused wrong `Class::IsInSamePackage()` result
for proxy classes if the packages name contained at least
one character outside the BMP plane.

This essentially reverts commit
    e16dad1d6388b0305f13e2171308a77f42e7c682
but keeps all tests, only updating expectations.

Also rename `CountUtf8Bytes()` to `CountModifiedUtf8Bytes()`
to make the format explicit in the function name.

Test: New test 181-proxy-non-bmp
Test: m test-art-host-gtest
Test: testrunner.py --host --optimizing
Bug: 192935764
Bug: 193141629
Change-Id: I8e6e8b08174c7a6d3ff84b0e1e929056b3947785

0 files changed, 0 insertions, 0 deletions