Sparse native theme representation

Themes are represented in the native layer using an array where the
entry id of resource ids are used to index into the array. This causes
native allocation size of a theme to correlate with the largest
attribute resource id in the styles applied to the theme.

From manual testing, I determined that on average in 1P apps and
system_server only 10-20% of the space allocated for themes actually
hold theme attribute values and the rest is empty/unused space.

Using std::vector and std::lower_bound to create a sparse array
representation will reduce amount of memory allocated by themes while
having a minimal impact on the performance of querying the attributes
defined in a theme.

From testing with ResourcesPerfWorkloads, this increased time spent in
the resources synthetic benchmarks by ~1%.

Bug: 141198925
Test: atest libandroidfw_tests
Test: atest ResourcesPerfWorkloads
Change-Id: Iec512b31b0545b0898ff248cd23f074a20fff45d

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