Allow 'continue' statements in 'foreach' loops.

tests/foreach-26.ispc

@@ -0,0 +1,24 @@
+
+export uniform int width() { return programCount; }
+
+
+uniform int foo(int i);
+
+export void f_f(uniform float RET[], uniform float aFOO[]) {
+    uniform int x[21];
+    for (uniform int i = 0; i < 21; ++i)
+        x[i] = i;
+
+    foreach (i = 0 ... 21) {
+        if (x[i] != 12345)
+            continue;
+        x[i] = 1;
+    }
+
+    RET[programIndex] = x[min(programIndex, 20)];
+}
+
+
+export void result(uniform float RET[]) {
+    RET[programIndex] = min(programIndex, 20);
+}