Use IntFunction for inspector flag and enum mapping

Use IntFunction for inspector flag and enum mapping

+ Remove IntEnumMapping class, (use a bound lambda of
  SparseArray#get(int) instead).
+ Remove IntFlagMapping.Builder, and make IntFlagMapping mutable. The
  immuability guarantees are provided by using a lambda of
  IntFlagMapping#get(int).
+ Change PropertyMapper#mapIntEnum(String, int, IntFunction<String>)
  and #mapIntFlag(String, int, IntFunction<Set<String>>) to take
  IntFunctions instead of semantic types.
+ Changes to the annotation processor to support code generation for the
  lambdas and additional internal cleanups.

Bug: 124448834
Test: atest --host view-inspector-annotation-processor-test
Change-Id: I3e7ccac63d50caa6ff49be1e78732831886e7f6e