[LIT] emit timeout error message only if timeout was reached

[AlexeySachkov]

Summary

This improves readability of LIT output: previously
error messages gets emitted that say that there was no error:

error: command reached timeout: False

[delcypher]

@AlexeySachkov LGTM provided the lit tests continue to pass.

[mgorny]

LGTM.

llvm/trunk/utils/lit/lit/TestRunner.py

for i,result in enumerate(results):
             # On Windows, a negative exit code indicates a signal, and those are
             # easier to recognize or look up if we print them in hex.
             if litConfig.isWindows and result.exitCode < 0:
                 codeStr = hex(int(result.exitCode & 0xFFFFFFFF)).rstrip("L")
             else:
                 codeStr = str(result.exitCode)
             out += "error: command failed with exit status: %s\n" % (
                 codeStr,)
-        if litConfig.maxIndividualTestTime > 0:
+        if litConfig.maxIndividualTestTime > 0 and result.timeoutReached:
             out += 'error: command reached timeout: %s\n' % (
                 str(result.timeoutReached),)
 
     return out, err, exitCode, timeoutInfo
 
 def executeScript(test, litConfig, tmpBase, commands, cwd):
     bashPath = litConfig.getBashPath()
     isWin32CMDEXE = (litConfig.isWindows and not bashPath)