c++: Use in-process client when networking is disabled

c++: Use in-process client when networking is disabled

Without the patch, the output for bad-mapper-3.C would be:

/src/gcc/gcc/testsuite/g++.dg/modules/bad-mapper-3.C:2:1: error: unknown Compiled Module Interface: no such module

As this line is unexpected, the test case would fail.
The same problem can also be seen for g++.dg/modules/bad-mapper-2.C.

gcc/cp/ChangeLog:

	* mapper-client.cc: Use in-process client when networking is
	disabled.

gcc/testsuite/ChangeLog:

	* g++.dg/modules/bad-mapper-3.C: Update dg-error pattern.

Co-Authored-By: Yvan ROUX <yvan.roux@foss.st.com>
Signed-off-by: Torbjörn SVENSSON <torbjorn.svensson@foss.st.com>