adb: implement LZ4 compression.

Add support for LZ4 compression, which compresses and decompresses far
more quickly than brotli, at the cost of worse compression ratio.

`adb sync -d system` speeds (in MB/s) on aosp_blueline-eng:

           none    brotli    lz4
USB 3.0     120       110    190
USB 2.0      38        75     63

Bug: https://issuetracker.google.com/150827486
Test: python3 -m unittest test_device.FileOperationsTest{Uncompressed,Brotli,LZ4}
Change-Id: Ibef6ac15a76b4e5dcd02d7fb9433cbb1c02b8382
diff --git a/adb/Android.bp b/adb/Android.bp
index 12d9a14..6386a78 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -470,6 +470,7 @@
         "libadbd_core",
         "libbrotli",
         "libdiagnose_usb",
+        "liblz4",
     ],
 
     shared_libs: [
@@ -571,6 +572,7 @@
         "libbrotli",
         "libcutils_sockets",
         "libdiagnose_usb",
+        "liblz4",
         "libmdnssd",
     ],
 
@@ -605,6 +607,7 @@
         "libadbd_services",
         "libasyncio",
         "libcap",
+        "liblz4",
         "libminijail",
         "libssl",
     ],