Add LOAD FRAGMENT pc test (#800)

Reproduces a reported problem, fix pending

test/link/load-fragment/a.asm

@@ -0,0 +1,4 @@
+SECTION "main", ROM0
+LOAD FRAGMENT "test", SRAM
+	db 0
+ENDL

test/link/load-fragment/b.asm

@@ -0,0 +1,7 @@
+
+SECTION "SECTION2", ROM0
+LOAD FRAGMENT "test", SRAM
+    jr Label
+Label:
+	dw Label
+ENDL

test/link/test.sh

@@ -130,13 +130,24 @@ rgblinkQuiet -o $gbtemp2 $otemp
 tryCmp $gbtemp $gbtemp2
 rc=$(($? || $rc))
 
+i="load-fragment.asm"
+startTest
+$RGBASM -o $otemp load-fragment/a.asm
+$RGBASM -o $gbtemp2 load-fragment/b.asm
+rgblinkQuiet -o $gbtemp $otemp $gbtemp2 2>$outtemp
+tryDiff load-fragment/out.err $outtemp
+rc=$(($? || $rc))
+dd if=$gbtemp count=1 bs=$(printf %s $(wc -c < load-fragment/out.gb)) > $otemp 2>/dev/null
+tryCmp load-fragment/out.gb $otemp
+rc=$(($? || $rc))
+
 i="overlay.asm"
 startTest
 $RGBASM -o $otemp overlay/a.asm
 rgblinkQuiet -o $gbtemp -t -O overlay/overlay.gb $otemp > $outtemp 2>&1
-# This test does not trim its output with 'dd' because it needs to verify the correct output size
 tryDiff overlay/out.err $outtemp
 rc=$(($? || $rc))
+# This test does not trim its output with 'dd' because it needs to verify the correct output size
 tryCmp overlay/out.gb $gbtemp
 rc=$(($? || $rc))