Copying sun.misc.Unsafe to jdk.internal.misc

From OpenJDK 10 onward, sun.misc.Unsafe has been moved to
jdk.internal.misc. Trying to merge in changes from OpenJDK 11
depends on having jdk.internal.misc.Unsafe available. As
sun.misc.Unsafe is still used throughout libcore code, it cannot
be changed yet, so a copy is made to jdk.internal.misc.Unsafe for
now.

As OpenJDK 11 is merged in and sun.misc.Unsafe references will
disappear, it can be deprecated and eventually made to call into
jdk.internal.misc.Unsafe.

Test: m
Test: art/test/testrunner/testrunner.py -t 004-UnsafeTest
Test: art/test/testrunner/testrunner.py -t 2235-JdkUnsafeTest
Bug: 190470684
Change-Id: I472a9778a1001fbd7c3ecce0dfa58ea6d632f158
30 files changed