Select expected remote libc++ library name based on remote platform.

[flackr]

Summary

Select expected remote libc++ library name based on remote platform. This is used to verify libc++ is in the loaded image list by various tests which use it.

[clayborg]

lgtm

lldb/trunk/test/lldbtest.py

def getLLDBLibraryEnvVal(self):
         if existing_library_path:
             return "%s:%s" % (existing_library_path, self.lib_dir)
         elif sys.platform.startswith("darwin"):
             return os.path.join(self.lib_dir, 'LLDB.framework')
         else:
             return self.lib_dir
 
     def getLibcPlusPlusLibs(self):
-        if sys.platform.startswith('freebsd') or sys.platform.startswith('linux'):
+        if self.getPlatform() == 'freebsd' or self.getPlatform() == 'linux':
             return ['libc++.so.1']
         else:
             return ['libc++.1.dylib','libc++abi.dylib']
 
 class TestBase(Base):
     """
     This abstract base class is meant to be subclassed.  It provides default
     implementations for setUpClass(), tearDownClass(), setUp(), and tearDown(),