basefilectx: move isexec and islink from memfilectx This will be used in the future for creating memctx objects from other store-type objects, such as a patch store or even another context.

tests: fix pyflakes test whitespace breakage

pushkey: wrap pushkey phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

push: wrap local phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

phase: wrap `hg phases` phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

mq: wrap qimport phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

mq: wrap qfinish phase movement in a transaction Phases are not yet inside the transaction, but we need to prepare for it. So we wrap the phase movement inside a transaction.

tests: change some #ifs to #requires

tests: replace exit 80 with #require

run-tests: add #require to abort full test This allows nuking a bunch of ugly hghave || exit 80 lines.