[subset] Fix run-shape-fuzzer-tests.py. It was generating incorrect paths for input fonts.

test/fuzzing/run-shape-fuzzer-tests.py

diff --git a/test/fuzzing/run-shape-fuzzer-tests.py b/test/fuzzing/run-shape-fuzzer-tests.py
index 088b36a..43378d1 100755
--- a/test/fuzzing/run-shape-fuzzer-tests.py
+++ b/test/fuzzing/run-shape-fuzzer-tests.py
@@ -19,10 +19,12 @@
 print ('hb_shape_fuzzer:', hb_shape_fuzzer)
 fails = 0
 
-for line in open (os.path.join (srcdir, "..", "shaping", "data", "in-house", "tests", "fuzzed.tests")):
+parent_path = os.path.join (srcdir, "..", "shaping", "data", "in-house", "tests")
+for line in open (os.path.join (parent_path, "fuzzed.tests")):
 	font = line.split (":")[0]
+	font_path = os.path.join (parent_path, font)
 
-	p = subprocess.Popen ([hb_shape_fuzzer, os.path.join (srcdir, "..", "shaping", font)])
+	p = subprocess.Popen ([hb_shape_fuzzer, font_path])
 
 	if p.wait () != 0:
 		fails = fails + 1