Fix a bug in returning reshape() expressions

[bradcray]

One of the follow-ups I had lined up for the new aliasing reshape() capability was to determine why one of the four cases in returnReshape.chpl wasn't working even though the others were. Specifically, this call:

proc bar() {
  return reshape(A, {1..2, 1..2});
}

was getting a lifetime checking error about returning a scoped variable, when other similar calls like:

proc foo() {
  return reshape(A, 1..2, 1..2);
}

were not.

Digging into this a bit more, I'm still not entirely certain why the two cases were resulting in different behavior, though I did find that the foo() routine should have been getting a similar error, in that capturing its result into a variable and modifying it:

var B = foo();
B[1,1] = 5;

was resulting in a modification to 'A' as well, even though returning an array and storing it in a variable should result in a deep copy.

Once I realized this, it didn't take long to determine that this is another place in the compiler where the current logic determines the existence of an array view by virtue of the expression's type. Updating it to also look for the new FLAG_IS_ARRAY_VIEW flag fixed the aliasing issue while also resolving the original error about returning a scoped variable.

To lock this fix in, I updated the test to make it check that none of the modifications to the returned arrays resulted in a modification to the original.

While here, I also looked for other calls to isAliasingArrayType() that didn't have a similar check for the new flag and added the check, hoping to head off additional bugs down the road.

[bradcray]

@dlongnecke-cray : Here's another follow on from the reshape PR that I regret not having the time to dig into pre-release (as it revealed a bug in the 2.5 implementation). Would you be willing to review?