[lldb] Change test paths to resolve symlinks

This commit modifes the `getSourceDir()` and `getBuildDir()` functions
to use os.path.realpath to resolve symlinks in the Base test class used
for API tests.

A few tests were failing when the build and source directories were
located under a path that contained a symlink. These failures were
because of cases where the symlink would be resolve to its real path
in the source code, but the test code would try to match against
the path with the symbolic link.

Two failing tests were

  TestProcessLaunch.test_target_launch_working_dir_prop
  TestSourceManager.test_source_cache_dump_and_clear

The inferior used `TestProcessLaunch` prints out its working directory
using the `getcwd` function, which is not allowed to return symbolic
links in the path components. When testing against the output from
`getcwd` we should resolve the full path to match the expected output.

The `TestSourceManager` test sets a breakpoint on a main-copy.c file
that is copied into the build output directory.  The source manager
resolves this file to its real location. When testing the output from
the source cache we need to resolve the expected path to remove
symlinks.

Author: dmpots

lldb/packages/Python/lldbsuite/test/lldbtest.py

@@ -722,15 +722,17 @@ def clean_working_directory():
 
     def getSourceDir(self):
         """Return the full path to the current test."""
-        return os.path.join(configuration.test_src_root, self.mydir)
+        return os.path.realpath(os.path.join(configuration.test_src_root, self.mydir))
 
     def getBuildDirBasename(self):
         return self.__class__.__module__ + "." + self.testMethodName
 
     def getBuildDir(self):
         """Return the full path to the current test."""
-        return os.path.join(
-            configuration.test_build_dir, self.mydir, self.getBuildDirBasename()
+        return os.path.realpath(
+            os.path.join(
+                configuration.test_build_dir, self.mydir, self.getBuildDirBasename()
+            )
         )
 
     def makeBuildDir(self):