This seems to have been added as a result of misreading the spec, there is no
get() method, only a getter (which the spec names get()), but this is actually
the  operator. There are many webkit tests that explicitly test for the
fact that the get() method is abscent. Remove it to conform to the spec.
It seems that like get(), set(index, val) was added as a misreading of the spec.
There are only two set() methods defined in the spec:
void set(TypedArray array, optional unsigned long offset)
void set(type array, optional unsigned long offset)
The set(index, val) is handled by the = operator.
Additionally updated a few exception error strings to match WebKit.