ctest: update documentation for CTEST_MEMORYCHECK_TYPE

The AddressSanitizer value was not documented.

Also fix some typos.
ctest: add support for additional sanitizer options

Sanitizers receive options through their environment variable; support
user-specified options here.
tests: fix copy/paste from tsan -> asan comments
tests: set sanitizer options properly

Prior to this, these options were just being set in the environment.
Merge topic 'ctest-memcheck-sanitizers'

f25e431d tests: set sanitizer options properly
f0661bf3 tests: fix copy/paste from tsan -> asan comments
ca9cc25c ctest: add support for additional sanitizer options
0b9ffffc ctest: update documentation for CTEST_MEMORYCHECK_TYPE