[analyzer] Don't emit extra context arrow after returning from an inlined call.

In this code

  int getZero() {
    return 0;
  }

  void test() {
    int problem = 1 / getZero(); // expected-warning {{Division by zero}}
  }

we generate these arrows:

    +-----------------+
    |                 v
    int problem = 1 / getZero();
                  ^   |
                  +---+

where the top one represents the control flow up to the first call, and the
bottom one represents the flow to the division.* It turns out, however, that
we were generating the top arrow twice, as if attempting to "set up context"
after we had already returned from the call. This resulted in poor
highlighting in Xcode.

* Arguably the best location for the division is the '/', but that's a
  different problem.

<rdar://problem/13326040>

llvm-svn: 179350