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/include/applypatch/applypatch.h

@@ -36,12 +36,11 @@ struct FileContents {
   struct stat st;
 };
 
-// When there isn't enough room on the target filesystem to hold the
-// patched version of the file, we copy the original here and delete
-// it to free up space.  If the expected source file doesn't exist, or
-// is corrupted, we look to see if this file contains the bits we want
-// and use it as the source instead.
-#define CACHE_TEMP_SOURCE "/cache/saved.file"
+// When there isn't enough room on the target filesystem to hold the patched version of the file,
+// we copy the original here and delete it to free up space.  If the expected source file doesn't
+// exist, or is corrupted, we look to see if the cached file contains the bits we want and use it as
+// the source instead.  The default location for the cached source is "/cache/saved.file".
+extern std::string cache_temp_source;
 
 using SinkFn = std::function<size_t(const unsigned char*, size_t)>;