Add new LocalUpdatableMaps benchmarks.

In addition, move a couple of elf benchmarks out of unwind_benchmarks.cpp
to the ElfBenchmarks.cpp file.

Test: Ran benchmarks.
Change-Id: I169f89f7b2dd6735568143f2176301e181fb8262
diff --git a/libunwindstack/Android.bp b/libunwindstack/Android.bp
index f3d3f27..601904a 100644
--- a/libunwindstack/Android.bp
+++ b/libunwindstack/Android.bp
@@ -411,6 +411,7 @@
     srcs: [
         "benchmarks/unwind_benchmarks.cpp",
         "benchmarks/ElfBenchmark.cpp",
+        "benchmarks/MapsBenchmark.cpp",
         "benchmarks/SymbolBenchmark.cpp",
         "benchmarks/Utils.cpp",
     ],