test: Modify 586-checker-null-array-get for javac/dx

Previously 1 of the methods were failing checker with javac/dx.
Move their old bytecode to a smali file to retain testing of those
optimizations.

Rewrite the checker tests in Main.java to use the javac/dx-generated
bytecode.

Test: art/test/run-test --64 --host --optimizing --build-with-javac-dx 586-checker-null-array-get
Bug: 62950048
Bug: 36902714
Change-Id: Ib320509422a358e116c24bb1b33442c0cf09ba25