Disable static memory under QEMU on CI (#1895)

* Enable the spec::simd::simd_align test for AArch64

Copyright (c) 2020, Arm Limited.

* Disable static memory under QEMU on CI

This commit disables the usage of "static" memory on CI and instead
forces all memories to be "dynamic" meaning that they reserve much
smaller chunks of memory. This causes the QEMU process's memory to
drastically drop (10GiB -> 600MiB) and should allow us to keep enabling
tests without hitting the OOM killer on CI.

Closes #1871 (includes that)
Closes #1893

* Fix typo

Co-authored-by: Anton Kirilov <anton.kirilov@arm.com>

.github/workflows/main.yml

@@ -327,6 +327,10 @@ jobs:
         upcase=$(echo ${{ matrix.target }} | awk '{ print toupper($0) }' | sed 's/-/_/g')
         echo ::set-env name=CARGO_TARGET_${upcase}_RUNNER::$HOME/qemu/bin/${{ matrix.qemu }}
         echo ::set-env name=CARGO_TARGET_${upcase}_LINKER::${{ matrix.gcc }}
+
+        # See comments in the source for why we enable this during QEMU
+        # emulation.
+        echo ::set-env name=WASMTIME_TEST_NO_HOG_MEMORY::1
       if: matrix.target != '' && matrix.os == 'ubuntu-latest'
 
     # Install wasm32-wasi target in order to build wasi-common's integration