Fix crash in compile on invalid methods with DebugInfoPlugin
Fix crash in compile on invalid methods with DebugInfoPlugin

The DebugInfoPlugin requests the text and temp maps for every method
selected. The Compiler crashes attempting to create the temp map if the
method fails to compile.

dolphinsmalltalk/Dolphin,jgfoster/Dolphin,dolphinsmalltalk/Dolphin,jgfoster/Dolphin,dolphinsmalltalk/Dolphin,dolphinsmalltalk/Dolphin,objectarts/Dolphin,jgfoster/Dolphin,objectarts/Dolphin,jgfoster/Dolphin