RFR JDK-8173777: Merge javac -Xmodule into javac--patch-module

[Jan Lahoda]

Hi,

I'd like to ask for a review of a patch that merges the -Xmodule: 
functionality into --patch-module. After this patch, the input source 
files are matched against modules patched with --patch-module, and are 
compiled as-if they were part of the module they are patching. (In the 
multi-module mode, patches for more than one module can be compiled, in 
the single-module mode, patches for only one module can be compiled.)

Removal of the -Xmodule: option will need adjustments in several 
repositories, as tests in multiple repositories are currently using 
-Xmodule:, and also jtreg is using the option. The current patch hence 
preserves the existing -Xmodule: functionality, although the option is 
hidden and no longer announced in help. I think it would be good to push 
the javac/langtools change proposed below, and then continue with other 
repositories.

The langtools patch is here:
http://cr.openjdk.java.net/~jlahoda/8173777/langtools.00/

(note it also contains changes to jshell and javadoc).

Proposed jdk repository changes are here:
http://cr.openjdk.java.net/~jlahoda/8173777/jdk.00/

How does this look?

Any feedback is welcome.

Thanks,
      Jan