PR guile/17146 preparatory work.

PR guile/17146 preparatory work.

	* data-directory/Makefile.in (GUILE_FILES): Add support.scm.
	* guile/lib/gdb/support.scm: New file.
	* guile/guile.c (gdbscm_init_module_name): Change to "gdb".
	* guile/lib/gdb.scm: Load gdb/init.scm as an include file.
	All uses updated.
	* guile/lib/gdb/init.scm (SCM_ARG1, SCM_ARG2): Moved to support.scm.
	All uses updated.
	(%assert-type): Ditto, and renamed to assert-type.
	(%exception-print-style): Delete.

	testsuite/
	* gdb.guile/types-module.exp: Add tests for wrong type arguments.