--harmony-sloppy-function depends on --harmony-sloppy

The lack of marking this dependency led to a ClusterFuzz crash when
sloppy-function was on but not sloppy. This case does not make sense.

R=adamk
LOG=N
BUG=chromium:520891

Review URL: https://codereview.chromium.org/1316773004

Cr-Commit-Position: refs/heads/master@{#30364}

src/flag-definitions.h

@@ -245,6 +245,7 @@ HARMONY_SHIPPING(FLAG_SHIPPING_FEATURES)
 
 // Feature dependencies.
 DEFINE_IMPLICATION(harmony_sloppy_let, harmony_sloppy)
+DEFINE_IMPLICATION(harmony_sloppy_function, harmony_sloppy)
 
 
 // Flags for experimental implementation features.