Don't Valgrind into java children in unit tests

...similarly to desktop/scripts/soffice.sh preventing that for LO itself.

One problem is that, even if it does not find any errors, Valgrind writes onto
a traced child's stderr, and when jvmfwk searches for a JRE to use, it takes
output to stderr into account, so would start to behave differently when run
under Valgrind.

--trace-children-skip appears to be new since Valgrind 3.6, and older versions
would probably fail early when they see this unknown-to-them option.  If this
turns out to be a problem in practice (current version is 3.9), we probably need
to make this conditional on a configure.ac check.

Change-Id: Ia6a72bdcd666d68ed0539170f3fc476292e82b96

solenv/gbuild/CppunitTest.mk

@@ -27,7 +27,7 @@ gb_CppunitTest__interactive := $(true)
 endif
 
 ifneq ($(strip $(VALGRIND)),)
-gb_CppunitTest_VALGRINDTOOL := valgrind --tool=$(VALGRIND) --num-callers=50 --error-exitcode=1 --trace-children=yes --leak-check=no
+gb_CppunitTest_VALGRINDTOOL := valgrind --tool=$(VALGRIND) --num-callers=50 --error-exitcode=1 --trace-children=yes --trace-children-skip='*/java,*/gij' --leak-check=no
 ifeq ($(strip $(VALGRIND)),memcheck)
 G_SLICE := always-malloc
 GLIBCXX_FORCE_NEW := 1