buildsys: remove surplus slashes from test dir paths

cosmetics

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

test/Makefile

@@ -46,9 +46,9 @@ test check all: run
 
 run: compile subdirs_run
 
-compile: $(top_builddir)/$(LOCAL_INSTALL_PATH) subdirs_compile
+compile: $(top_builddir)$(LOCAL_INSTALL_PATH) subdirs_compile
 
-$(top_builddir)/$(LOCAL_INSTALL_PATH):
+$(top_builddir)$(LOCAL_INSTALL_PATH):
 	$(Q)$(MAKE) -C $(top_builddir) $(LOCAL_INSTALL_PATH)
 
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