Annex B: f() = g() in non-strict mode raises SyntaxError at parse; should be runtime ReferenceError

[Oichkatzelesfrettschen]

Annex B sec-runtime-errors-for-function-call-assignment-targets requires that CallExpression as an assignment LHS in non-strict code is valid syntax that throws ReferenceError at runtime. Boa rejects it at parse time.

Repro (non-strict):

function f() { return {}; }
function g() { return 1; }
f() = g();   // should throw ReferenceError at runtime
f() += 1;
++f();
f()++;
for (f() in []) {}

Expected: ReferenceError at runtime
Got: SyntaxError: Invalid left-hand side in assignment at parse time

Spec: https://tc39.es/ecma262/#sec-runtime-errors-for-function-call-assignment-targets

Fix: In the parser, when the LHS of an assignment is a CallExpression in non-strict mode, accept the syntax and emit a runtime ReferenceError instead of a parse error.

Failing test262: annexB/language/expressions/assignmenttargettype/ (7 cases)