Reduce memory used by CompiledMethods.

Use LengthPrefixedArray<>s instead of SwapVector<>s to store
CompiledMethod data and get rid of the unnecessary members
of CompiledMethod to reduce dex2oat memory usage. Refactor
the deduplication from CompilerDriver to a new class.

Use HashSet<> instead of std::set<> for the DedupeSet<> to
further decrease the memory usage and improve performance.

This reduces the dex2oat memory usage when compiling boot
image on Nexus 5 (with Optimizing, -j1) by ~6.75MiB (5%).
This also reduces the compile time by ~2.2% (~1.6% dex2oat
time; with Optimizing, without -j).

Change-Id: I974f1f5e58350de2bf487a2bca3907fa05fb80ea
diff --git a/compiler/Android.mk b/compiler/Android.mk
index 17f9d12..4ae1403 100644
--- a/compiler/Android.mk
+++ b/compiler/Android.mk
@@ -54,6 +54,7 @@
 	dex/verification_results.cc \
 	dex/vreg_analysis.cc \
 	dex/quick_compiler_callbacks.cc \
+	driver/compiled_method_storage.cc \
 	driver/compiler_driver.cc \
 	driver/compiler_options.cc \
 	driver/dex_compilation_unit.cc \