run-make: skip issue-36710 on riscv64

The test assumes it can run target binaries on the host. This not true
for riscv64 CI (or for other platforms using remote-test-server).

Author: tblah

src/test/run-make/issue-36710/Makefile

@@ -1,3 +1,6 @@
+# ignore-riscv64 $(call RUN,foo) expects to run the target executable natively
+#                              so it won't work with remote-test-server
+
 include ../../run-make-fulldeps/tools.mk
 
 all: foo