Allow 'continue' statements in 'foreach' loops.

tests/foreach-30.ispc

@@ -0,0 +1,20 @@
+
+export uniform int width() { return programCount; }
+
+
+uniform int foo(int i);
+
+export void f_fu(uniform float RET[], uniform float aFOO[], uniform float ub) {
+    RET[programIndex] = 0;
+    
+    foreach (i = 0 ... 10, j = 0 ... programCount + 1) {
+        if (i == 5)
+            continue;
+        if (j > 0)
+            ++RET[j-1];
+    }
+}
+
+export void result(uniform float RET[]) {
+    RET[programIndex] = 9;
+}