test suite update - gdb.base/[efg]

test suite update - gdb.base/[efg]

Convert files gdb.base/[efg]*.exp to use standard_output_file et al.

	* ena-dis-br.exp, enum_cond.exp, enumval.exp, environ.exp,
	eu-strip-infcall.exp, eval-skip.exp, exe-lock.exp,
	expand-psymtabs.exp, exprs.exp, fileio.exp, find.exp,
	fixsection.exp, foll-exec.exp, foll-fork.exp,
	fortran-sym-case.exp, frame-args.exp, freebpcmd.exp, fullname.exp,
	funcargs.exp, gcore-buffer-overflow.exp, gcore.exp, gdb1090.exp,
	gdb11530.exp, gdb11531.exp, gdb1250.exp, gdb1555.exp, gdb1821.exp,
	gdbindex-stabs.exp, gdbvars.exp, gnu-ifunc.exp, gnu_vector.exp:
	Use standard_testfile, standard_output_file, prepare_for_testing,
	clean_restart.