Avoid creating compiled_methods_ array unnecessarily

For compiler filters that don't quicken or compile, avoid creating
the compiled method arrays to save RAM.

For a dex2oat of a large app with verify filter -j4 on the host:
Reduce native alloc from 39MB to 35MB
Maximum resident set size (kbytes): 287592k -> 282696k

Bug: 63467744
Test: test-art-host
Change-Id: Ib84fd9337dc7f5f1e32017bf2c392d1d3328fba8