Per ProxyCreate() (https://tc39.github.io/ecma262/#sec-proxycreate), a Proxy
is only given a [[Call]] slot if the target has a [[Call]] slot as well. This
was previously implemented correctly for [[Construct]], but not for [[Call]].

BUG=v8:4797, v8:4796, v8:1543
LOG=N
R=cbruni@chromium.org, neis@chromium.org, adamk@chromium.org, littledan@chromium.org

Review URL: https://codereview.chromium.org/1752133004

Cr-Commit-Position: refs/heads/master@{#34461}