Update escaping in Android.bp files

Strings like cflags in Android.bp files are parsed by blueprint,
written to build.ninja files, parsed by ninja, and then passed to
/bin/sh -c.  This had resulted in a combination of blueprint
(\"), ninja ($$), and shell (\$) escaping being necessary.

Soong has been updated to automatically handle ninja and shell
escaping, remove extra escaping from Android.bp files.

Bug: 31221587
Test: m -j
Change-Id: Ib58a51dee8d22296b69ec21768ba6a49dd60e980
diff --git a/tests/Android.bp b/tests/Android.bp
index defd76c..4caaa54 100644
--- a/tests/Android.bp
+++ b/tests/Android.bp
@@ -361,7 +361,7 @@
                 "libutils",
             ],
             ldflags: [
-                "-Wl,--rpath,\\$${ORIGIN}/../bionic-loader-test-libs",
+                "-Wl,--rpath,${ORIGIN}/../bionic-loader-test-libs",
                 "-Wl,--enable-new-dtags",
             ],
         },