Switch to bionic gtest in bootable/recovery

We encountered segfaults in Imgdiff host tests due to the failure to
reset states of getopt. The problem can be solved by switching to use
bionic's gtest where a new process is forked for each test.

Also modify the recovery_component_test to make sure it runs in parallel.
Changes include:
  1. Merge the writes to misc partition into one single test.
  2. Change the hard coded location "/cache/saved.file" into a configurable
  variable.

Bug: 67849209
Test: recovery tests pass

Change-Id: I165d313f32b83393fb7922c5078636ac40b50bc2

applypatch/freecache.cpp

@@ -90,10 +90,9 @@ static std::set<std::string> FindExpendableFiles() {
     while ((de = readdir(d.get())) != 0) {
       std::string path = std::string(dirs[i]) + "/" + de->d_name;
 
-      // We can't delete CACHE_TEMP_SOURCE; if it's there we might have
-      // restarted during installation and could be depending on it to
-      // be there.
-      if (path == CACHE_TEMP_SOURCE) {
+      // We can't delete cache_temp_source; if it's there we might have restarted during
+      // installation and could be depending on it to be there.
+      if (path == cache_temp_source) {
         continue;
       }