Stable-symbol-names test: compare only global symbols

With MinGW and specific flags symbol may end up in multiple sections in some cases like:
0000000000000000 p .pdata$_ZN20stable_symbol_names113mono_function17hd4880e88dec8766dE
0000000000000000 t .text$_ZN20stable_symbol_names113mono_function17hd4880e88dec8766dE
0000000000000000 r .xdata$_ZN20stable_symbol_names113mono_function17hd4880e88dec8766dE
0000000000000000 T _ZN20stable_symbol_names113mono_function17hd4880e88dec8766dE

This will cause an error when comparing that output directly with other library
that only imports the symbol since it will appear only once.
To avoid the issue pass "-g" to nm so only the global symbol (the one
with "T" letter) will be listed.

Author: mati865

src/test/run-make-fulldeps/stable-symbol-names/Makefile

@@ -9,7 +9,7 @@
 #  4. sort those symbol names for deterministic comparison
 #  5. write the result into a file
 
-dump-symbols = nm "$(TMPDIR)/lib$(1).rlib" \
+dump-symbols = nm -g "$(TMPDIR)/lib$(1).rlib" \
              | grep -E "$(2)" \
              | sed -E "s/.*(_ZN.*E|_R[a-zA-Z0-9_]*).*/\1/" \
              | sort \