Remove CHECK in AdjustEncodedValue.

The CHECK(encoding != DW_EH_PE_aligned) can trip given the right
arguments. This check isn't necessary, since the code will return
false in that case.

Add new unit test that tries all values to make sure no CHECK fires.

Bug: 120968571

Test: Passes new unit test, and passes fuzzing that failed before.
Change-Id: I062bcd18508c75cd3a4ca9dd12f922e25aafda8a