[host] Remove calls to fbl::AutoCall

fbl::AutoCall is deprecated in host/userspace in favor of fit::defer.

Calls to fbl::AutoCall could not be removed from kernel or system code
since they may not have the C++ standard library included.

TEST=runtests
CP-146: #progress

Change-Id: Ief2f908430c17851f9f40e4bbabbe122005033d6

[compiler.h][fs] Remove DISABLE_THREAD_ANNOTATIONS from compiler.h

This mechanism is used by some filesystem code to conditionally
disable thread annotations. This is done for the sake of also building
code on the host.

This logic is specific to the filesystem code, and should not be part
of the public Zircon ABI. As such, this CL moves the conditionals into
the filesystem code itself.

Test: built with all compilers; CQ for mac; manually broke threading
analysis to verify that clang is still running the instrumentation.

Change-Id: I9c6453198c637fd03c1238d1c9790cb69ba11b6a

[fs] Avoid inlining BlockTxn, create host ulib/fs library

Test: CQ

Change-Id: I70db599252fcc0620e69cf6ce4a35cece628a261

[fzl] Move fs::MappedVmo to fzl::MappedVmo

This is a useful utility outside of the scope of just filesystems.

Change-Id: Id9cfa3d40e7d45dd6dd94242c1a85204f1139bfa
Tested: Run `runtests`

[build] introduce hosttest module type

These get installed in $(BUILDDIR)/tests but otherwise are
just like hostapp modules.

Update existing host tests to use this module type.

Change-Id: Ic981d98a28faaa16699967e6263ecac5044bafc8

[blobstore] Rename blobstore to blobfs

Also, mount blobfs at /blob rather than /blobstore.

Change-Id: Ifdc473752ede37b909b30e35dbaac1397565a659

[fvm] Add host & target side support for compressed sparse file

Change-Id: I2ba9350cfbc98e96de7fc0a7a253e9c560ba208b

[minfs][blobstore][fvm] Relocate host-side tools to /host

Change-Id: I21e3f17a7dd926dc5038af85edc0e2e016d220bd

[digest] Switch from cryptolib to uboringssl

This CL switches the SHA-256 implementation for ulib/digest to use
uboringssl, which includes optimized assembly and hardware acceleration
to provide better message digest performance.

Change-Id: Id3dedbc8232b4f4491b19fe46ef9e1415eea7358

[blobstore] Convert Blobstore to a library

ZX-1380 #comment In Progress

Change-Id: I32c59b89eb0a5c10f44b0f391f950f9174279434

[minfs] Convert MinFS to a library

ZX-1314 #comment In Progress

Change-Id: I0a7672d8321e0be07dd4c66232a0b4836db777a3

[fvm] Add tests for host-side tool

Change-Id: Icb91281d15d60531380de0697989686f53dca96e