Reland: [flutter_tool] Where possible, catch only subtypes of Exception - #52021

With asserts enabled, this catch was previously catching an assertion failure, and defaulting to arm64:

With asserts not enabled, nothing was caught and the architecture would be propagated through the build as null, which just happened to work, I guess by accident.

When this PR changed getIOSArchForName() to throw an Exception instead of assert, and the catch was changed to catch an Exception, we correctly(?) fell back on the default of arm64 as the comment under the catch seems to intend. However if the device was actually an armv7f device, then we'd propagate the wrong architecture, leading to a failure from ios_deploy in the device lab.

To try to fix this, I've added a case to getIOSArchForName() to handle armv7f.

ptal