Change session log filename pattern: test before arch

[vharron]

Summary

This is a very minor change.

Just reshuffle the elements of the log filename so that the test name comes before the arch/compiler

Before:
Failure-x86_64-clang-TestCModules.CModulesTestCase.test_expr_with_dwarf.log

After:
Failure-TestCModules.CModulesTestCase.test_expr_with_dwarf-x86_64-clang.log

This way, results are grouped by test name, not by arch. I think this is much more useful.

[clayborg]

Looks good.

lldb/trunk/test/lldbtest.py

def getLogBasenameForCurrentTest(self, prefix=None):
         if not os.path.isdir(dname):
             os.mkdir(dname)
 
         compiler = self.getCompiler()
 
         if compiler[1] == ':':
             compiler = compiler[2:]
 
-        fname = "{}-{}-{}".format(self.getArchitecture(), "_".join(compiler.split(os.path.sep)), self.id())
+        fname = "{}-{}-{}".format(self.id(), self.getArchitecture(), "_".join(compiler.split(os.path.sep)))
         if len(fname) > 200:
-            fname = "{}-{}-{}".format(self.getArchitecture(), compiler.split(os.path.sep)[-1], self.id())
+            fname = "{}-{}-{}".format(self.id(), self.getArchitecture(), compiler.split(os.path.sep)[-1])
 
         if prefix is not None:
             fname = "{}-{}".format(prefix, fname)
 
         return os.path.join(dname, fname)
 
     def dumpSessionInfo(self):
         """