Add more tests for things that only the external tests had covered

test/link/export-all/a.asm

@@ -0,0 +1,2 @@
+section "a", rom0[2]
+OneColon:

test/link/export-all/b.asm

@@ -0,0 +1,2 @@
+section "b", rom0[0]
+dw OneColon

test/link/export-all/ref.out.sym

@@ -0,0 +1,2 @@
+; File generated by rgblink
+00:0002 OneColon

test/link/test.sh

@@ -162,6 +162,17 @@ tryDiff "$test"/ref.out.sym "$outtemp2"
 tryCmpRom "$test"/ref.out.bin
 evaluateTest
 
+test="export-all"
+startTest
+"$RGBASM" -E -o "$otemp" "$test"/a.asm
+"$RGBASM" -o "$gbtemp2" "$test"/b.asm
+continueTest
+rgblinkQuiet -o "$gbtemp" -n "$outtemp2" "$otemp" "$gbtemp2" 2>"$outtemp"
+tryDiff "$test"/out.err "$outtemp"
+tryDiff "$test"/ref.out.sym "$outtemp2"
+tryCmpRom "$test"/ref.out.bin
+evaluateTest
+
 for test in fragment-align/*; do
 	startTest
 	"$RGBASM" -o "$otemp" "$test"/a.asm